It is quite simple for someone to ask what the best flash cart on the market is, however, the answer is difficult to come up with.  Every user has different needs, and different flash carts to tailor those needs.  The “best flash cart” is different among different users.

To find the “best flash cart”, I sent out a survey to some of the most experienced members in the flash cart scene.  Each answer is very unique and comes with their own justification of why they chose it.  Hopefully, you will realize what you need in a flash cart, and find one for you.

The message I sent out for the survey is quoted word for word here:

“Hi,

I just wanted to ask you about your opinions on DS flash carts with a sort of a survey.  I am sending this to you as well as other people with ample experience just to get an unbiased view of what the best flash cart in the market is.  I hope you can participate in this, as your opinion is very valuable.

Anyways, please don't answer these with one word answers, but backup your ideas, even if it is a sentence or two.

Question 1:  What do you think is the best flash cart to buy currently without considering the price?

Question 2:  What do you think is the best flash cart to buy currently with consideration of the price?

Question 3:  Which flash cart do you think changed the scene with its features, which cart was the best of its time?

Thank you for responding to these questions.  I just also wanted to add, I am going to use these comments and answers on my site, using direct quotes.  I will consolidate the answers of many people into one little post on my site.  This will probably be quite an effective answer for the many, many posts on various forums asking about the best flash cart.  I am sure new users will be pleased to hear your comments.

Thanks,
PharaohsVizier"

Here are the summarized results, but the most valuable information is in the few sentences each person submitted to justify their answers.

The answers are here, once again, are quoted word for word:

Costello – Reviewer and Administrator at GBATemp.net
1. With or without considering the price my answer will be the same: the R4 DS. Being one of the first slot-1 solutions (after the NinjaDS, and the DS-X) it has been constantly evolving with the kernel updates, adding always more and more features responding to people's demands. The R4 team either invents new great ideas, or re-uses existing ideas from the other adapters (ie. a recent example: DLDI auto-patching). And everything they do, they do it well and fast: their soft reset feature is the most reliable of all linkers/adapters. They're quick to react in case of problems - we saw this recently too with the release of Zelda DS. Seems like the R4 team will never let you down. The R4 DS OS is also very fast and responsive, ever since I started using my R4 DS I never felt the need to switch again. All the advantages of the R4 make it a great solution and our members have already realized it; a large community of R4 users has grown on many forums - GBAtemp.net being one of them.

2. Considering the price, the R4 DS comes even more as the best solution. One of the cheapest adapters on the market, and it has kept the same price range ever since it came out.

3. I think the DS-Xtreme was, back in september/october 2006 when it was released, the best slot-1 solution. It was the first adapter to fit in the DS slot and offered fantastic compatibility (back in the days...). I think the DS-Xtreme has defined a standard for flashcarts. However, ever since the R4 DS came out in early 2007, it hasn't ceased to amaze us with its low price range and its continous updates, which has again in my opinion defined a new standard for flashcarts. So my answer is double: both the DS-Xtreme and R4 DS came as "revolutions" in the domain of DS linkers/adapters.
Shaunj66 – Reviewer and Administrator at GBATemp.net
1.  CycloDS Evolution because it's feature rich and offers full download play support

2.  R4 DS because it's well established and does everything any user should need.

3.  DS-Xtreme because it raised the bar with its features and promises and English support. Unfortunately I wouldn't recommend or even use this cart now.
Opium – Reviewer and Supervisor at GBATemp.net
1.  R4DS, because of it's extensive feature list and great support. New features and updates come out all the time for the R4 which shows the team behind it is still going strong. The save system is also hassle free as you do not need to select save types.

2.  Again the R4DS, Amazing features and support and it is very cheap. I'd recommend a Japanese made Kingston 1GB micro SD to go with it, it is cheap, incredibly fast and will not result in any game slowdowns.

3.  Any slot-1 DS flashcard changed the scene. I remember the deep dark beginnings of DS homebrew with a passme sticking out. You needed a specific original game to make the ROM work. Moving into a purely slot-1 flashcard opened up DS homebrew and piracy to the mainstream. I congratulate the R4DS for being one of the simplest and most feature rich flashcards. It certainly helped bring DS flash cards to the mainstream scene as even a simpleton can use it.
Slade – Webmaster of EZFlash.Sosuke.com
1. I know with the slowness of the development of the EZ Carts I wouldn't buy one at this stage. There are other carts out there with much more advanced features than the EZ Carts currently offer. I've now noticed a lot of DS based flash carts are moving back to onboard memory (and non upgradeable), which I don't think is the best move, given how cheap microSD cards are and how fast they're becoming for read/write speeds.

2. Price wise, I'd still say if you're after a cheap good cart that plays DS games with no frills, then the EZV is hard to beat. The M3 Simply is great for just a few dollars more.

3. I'd have to say the EZFlash 3 did a huge amount for the GBA scene. It was one of the most highly respected carts of the time and really pushed the boundaries for features (cheats, soft reset, skinable loader, random access to games (ie can be added and deleted in any order)). What was innovative when it was released is now a minimum standard in todays flashcarts.
Sinkhead – Reviewer and Webmaster of RomNet.co.uk
1.  I believe the CycloDS Evolution is by far the most promising cart so far. While other carts promised features they didn't get until a few firmware releases later the Evolution did all it originally promised to do and more. The support team (Team Cyclops) is second to none at the moment, they are active on the forum and they listen to users and implement features for them. So the CycloDS Evolution is the best for me if money is no object.

2.  R4. Definitely. The support team aren't as active and there have been a few small problems with the spring (that can be easily fixed) however for it's low price and already great feature set you can't beat it. Especially as it's not picky about your memory card and only one or two games require a high-speed memory card to work. The R4 is definitely king if you're on a budget!

3.  Again I would say this is the R4. It brought modding to the masses, anyone could do it, it was cheap, easy and it worked. It's features weren't revolutionary in themselves but the sheer greatness of the card made it's competitors have to produce higher and higher quality products to even stand a chance against the R4.
PharaohsVizier – Reviewer and Webmaster of DSDatabase.org
1.  The CycloDS Evolution is easily the best cart on the market.  Other than the slight price difference, it has almost all of the features from other carts as well as some of their own.  You get functions such as cheats, slowdown, passme, and they have more that are unique to their own cart, the in game brightness.  They also seem to have a solid team behind it, making promises that seem unbelievable, but many of them have already been dealt with.

2.  The R4 is a great cart for its price, it offers full support for NDS games as well as cool features such as auto-DLDI patching.  Although it has been out for quite some time, it is still thriving because of the large community, and the ever hard working R4 team.  At prices as low at $30 each, the R4 just can’t be beaten when it comes to price.  Also, it is an incredibly easy flash cart to use, perfect for first time users.

3.  I believe the DS Link is the best cart of its time.  It is probably rarely heard, or even considered because it was overshadowed by the success and downfall of the DS Xtreme, then once again covered up by the release of the R4, however, it is genuinely a great cart, and still is a great option.  The DS Link was one of the first slot 1 flash carts, however, its downfall was caused by the lack of a built in passme, thus creating the problem that only flashme users are able to use the DS Link.  However, the DS Link pressed on despite their lack of success with updates almost every week to correct bugs and fix games.  One of the most important patches was patch 2.0, which fundamentally started the entire cheat system that most flash carts support.  The DS Link had been working on cheats since its release, when released, many of the other carts scrambled to release their own variations.  I found most of them not as good as the DS Link.  At release, the DS Link released three times as many pre-coded cheats as their competitors.  The DS Link was a great cart, probably one of the best, even today, however, it was created at a bad time and was completely ignored.
Mewgia – Reviewer at RomNet.co.uk
1.  The best DS flashcart to buy at this point in time, when not considering the price, would have to be the CycloDS Evolution. It is the most feature-rich cart out there, and it is very easy to use (apart from getting the MicroSD card out of the slot, my nails are considerably shorter now from trying to get that thing out ; ), the customer support is fabulous, and if you have a defective cart the team will replace it for free. Practically perfect

2.  The best cart to buy, when considering the price, is probably the R4. It is a very nice cart with a good set of features and has a very nice price. However, it lacks a few things that the Cyclo has, such as perfect download play support. It also doesn't have the great support that the Cyclo team gives.

3.  Erm...I haven't really been in the flashcart scene long enough to fully answer this question. Sorry!
ModMyDS.com – Flash Cart Reseller
1.  I would consider the M3 Lite/Passcard combo to be the best system without consideration to price. The DS was designed with both GBA and DS games in mind, so with the M3 Lite/Passcard setup you get everything out of your investment. Customers usually purchase the M3 Lite/Passcard set up, or the M3 Lite alone, however I have had people purchase the M3 Lite with various slot 1 cards, probably for use with the Opera Browser

2.  With consideration to price, I feel that the R4 is probably the best cart to buy. Sure, it limits you strictly to DS software, but it does everything so well. Simply drag and drop the software you want onto the microSD card, pop it in, and you're ready to go. If only the slot 2 cards were like it :). The R4 is currently the hottest selling flashcart on the market, and is sitting at #1 on ModMyDS.com's best seller list (closely followed by the M3 Simply). And no, I'm not saying it’s the best because it sells a lot. I personally own an R4 as well and am speaking from personal experience :)

3.  Hm… that's definitely a good question. I think the best cart of all time is any M3 SD variant (SD, miniSD, Lite). The only reason I gave the M3 Slot2 cards the best cart of all time award is because of the fact that they are compatible with pretty much everything. M3's interface, though relatively basic, is still fairly attractive (though I would rather use a custom skin) and its just overall an easier product to use. If it had touch functionality, it would have been a lot better, but that’s only a small sacrifice for a great product.
Recently there's been a decrease in the number of M3 Slot 2 cards sold - I'm assuming its because there aren't many more GBA games/homebrew coming out. Also, since the EZ 3 in 1 hit the market, the M3 slot 2 cards have become an extremely expensive solution to the Opera Browser RAM hack, since they cost nearly 3 times as much as the EZ 3 in 1. M3 sells a bit slower than Supercard and I believe thats only for one reason - the price. You can get a Supercard, with similar features (though not 100% compatibility that M3 boasts) for about $20-25 less than the M3.. which is about 33% savings. If M3 was a bit cheaper, I have no doubt in my mind that it would have been the top seller before Slot 1 cards came out.
cory1492 – Homebrew Developer
1.  Tough question, there is no real way I could pick one out of all. For versatility I'd have to say the M3 perfect lines, especially for those (tweakers?) that like messing with patcher options and having extra features on the GBA side of things. For homebrew uses, currently I'd have to say the EZ4 deluxe - it offers a large chunk of SRAM and PSRAM for those that wish to use it, it's relatively simple to get along with and best of all EZ team did not make it overly complicated to use from homebrew in a bid to protect their "IP". For ease of use with the DS, I'd have to say R4. Can't beat drag and drop when it comes to newbies who are "don't care, just make it work" types. For innovation I have to say Neo. The potential of Neo's DS products seems to have been entirely overlooked by many who took freebies to make homebrew with and then 180 to moan about commercial dump compatibility.
2.  R4 + EZ 3in1, for the budget price you cannot beat the feature list this combo gives as well as the compatibility for both GBA and NDS; homebrew or otherwise. I could easily buy 4 or 5 of these combos for the same price I purchased my F2A 1G card for, and still come out with many many gigs of space more with SD cards at their current prices and some solid hardware to work with.
3.  Features that changed everything... the introduction of the DS kernel to the SuperCard line sparked a lot of changes, and everyone has been following the general example since by pushing cards to market using removable multimedia cards wrather than overpriced single use flash chips. Even the GBAMP creators got left behind until they moved away from movies only cards.
Tikker – Moderator at forums.R4DS.net
1. M3 lite perfect. It's imo the best of the slot2 cards, and slot2 cards are the only flashcarts that can play homebrew, NDS and GBA titles. IMO it would be impossible to award this to a slot1 card since none of them can play GBA games. I also really like the moonshell implementation on the M3. the ability to watch the movie on both screens, with 1 reversed is kind of slick when you've got a few people huddled around the DS

so for perfect NDS and GBA compatibility, I've got to go with the M3 lite Perfect if every flashcart was the same price
2. R4DS/M3simply. Dirt cheap, great NDS compatibility and did I mention it's dirt cheap? also fairly decent sized community supporting them, with interesting management apps built specifically for these devices (Trolleyguy's R4 Commander, Hank's Rominator, etc)
3. GBAMP is probably the cart that opened things up the most, but the introduction of the slot1's has kind of started to bring the homebrew scene a little bit more mainstream
Öhr – Moderator at M3-Forum.com
1.  it depends if you want GBA support or if nds only is ok. also if you want to run homebrew etc.
Before "DLDI" was invented, the support of cards with the use of the filesystem was very limited. just a few worked(gbamp, m3 cf, sc cf, etc.). lots of those early projects do not work on the newest flashcards like cyclods, r4 or m3 lite. if you want to use your card mainly for homebrew, get yourself a M3 CF or a GBAMP(m3 preferred). If you want to get a flashcard, you have to decide whether you want a slot-2 card(GBA support!) or a slot-1 card. for slot-1, the best one is CycloDS Evolution. For Slot 2, you should get a Supercard lite or a m3 lite(because of the size). if you still have a phat ds and want a slot 2 card, get a m3 miniSD or a something similiar.
but remember: to run commercial and homebrew nds games with a slot 2 device, you have to get a passme or flash your ds! for gba, you dont need this.
2.  slot 1: m3 ds simply/r4 or supercard ds one
slot 2: m3 lite or sc microSD(not sure what its called and im too lazy took look this up)
since the m3/r4 support isnt that good, get a supercard!
3.  well, its the gbamp. it is one of the first flashcard for the gba/nds and had/has a great community. but if you want something "up to date", its the CycloDS Evolution.
the cyclods evolution has so far a great(lets say the greatest) support by the developers(i mean the cyclops team)!
it offers lots of completely new features like ingamemenu in which you can slow down the game if you want(0.5 speed!) return to mainmenu and whatever. currently they are working on a screenshot function and a realtime save function.
but thats not all: you can even request features. maybe your request becomes reality
conclusion:
if you have the money, get a CycloDS Evolution and if you want GBA support, get a m3 lite or something like this as well.
if you dont have much, look at 2.
cracker – Moderator at EZFlash.Sosuke.com
1. R4/m3 Simply would be my top pick for slot 1. The carts are stable, have good features, and supported very well. m3 for slot 2. Same reasons as before.

2. R4/m3 Simply. The price is similar to most other slot 1 carts that use removable media but it's still a sweet cart for the price you pay. The features you get for the money you spend is what it comes down to. As I mentioned before, the m3 line has very good support for their products and the immediate addition of features to the m3 carts shows this. I'm split over slot 2. Part of me wants to say the EZ4 Lite Deluxe and the other wants to say m3. The EZ4LD is great for playing most games on but it has it's fair share of save problems (esp with newer games), etc. I've never lost a save with my m3 cart and the only thing holding me back from making it my sole decision is the price. They are somewhere between 3-4x that of the EZ4LD and a lot of people are on a budget.

3. For slot 1 I am split because the DS Xtreme opened up the scene to slot 1 carts. At the time it was very exciting to see a flash cart the same size as an original DS game. Now that there are many carts to choose from (many which are feature rich) the DS Xtreme has lost its appeal. Currently the R4/m3 Simply seem to have the best set of features, support, and price point so that is my second pick. For slot 2 the m3 was (and still is) the best because of the features it has and the stability.
dantheman – Moderator at SCDev.info
1.  I'm really not big into the whole internal memory deal, so that narrows it down to external media devices.  Without considering price, I'd say the Supercard DS and a fast microSD card would be the best option to get, as long as you can guarantee that you're getting a fast enough microSD card.  It has numerous features specific to the device, and the Supercard team appears to supply regular updates.  However, this CycloDS Evolution device looks like a very good option as well, though I haven't heard enough about it to form a solid opinion about it yet.  For adding GBA support to the mix, an M3 Perfect (not Pro) would be the best option, again not considering price.

2.  The R4 or M3 Simply would probably be a good option.  You can afford to buy a slower microSD card if you don't wish to play the few problem games, and the device itself is cheaper.  In addition, it's still fully functional in terms of playing DS games, both commercial and homebrew.  For adding GBA support, the EZ-V 3in1 expansion pack is cheap yet effective.

3.  I'm not entirely sure how to answer that question.  Many devices have had key moments.  The R4 and M3 Simply are incredibly widespread now and have brought many users to the world of DS homebrew, in addition to being the first carts to offer cheats, which has changed the way games are played (for better or for worse, I'll let you decide on that one).  The EZ-V 3in1 expansion pack is an amazing addon for its price and allows users to have the best of both worlds, slot-1 and slot-2.  The DS-X, while overpriced and underfeatured now, nevertheless was the first slot-1 device to support the majority of homebrew programs, a major feat considering that DLDI had not yet been invented.  Each device has had an impact on the world of homebrew, no matter how insignificant that impact may have been.
FAST6191 – Moderator at EZFlash.Sosuke.com
1.  Best is always seriously subjective as well: I do not mind learning a bit and jumping through a few hoops if it means I end up with something better, others prize drag and drop/fire and forget. In terms of flash carts this could probably be compared with the EZ5 and R4: EZ5 needs a savelist but in doing so it should not need a patching update, the R4 patches roms and so occasionally needs an update.

DS slot versus GBA slot (or slot1 vs slot 2), the reason I have not upgraded is because my GBA slot stuff functions very nicely and still gives me GBA (there is a massive library of great games and the rom hacking/translation people have taken interest now the GBA is "dead").

2.  I still suggest people stick with something that has been proven for a few months like the m3dss, scone, ez5, r4 (expect perhaps a g6 real) as some of the newer cards still need to prove themselves (the neoflash 1 was for a time the best DS card, the DSX was similarly the best DS card for a while)

3.  Perhaps the early supercards: they pioneered external memory to an extent (the GBAMP came first as I recall but few really have one and it was not the nicest thing to use) but more importantly brought it mass market. Perhaps an honourable mention to the EZ3 for the NAND - RAM arrangement (as opposed to expensive old style bankswitched NOR).

I would also argue that software/ libraries have driven stuff and whoever gets themselves in those does seem to be the "best" for a time: early CF cards (GBAMP, m3, SC) and gba_nds_fat (compare this with the later source release/reverse engineering of the EZ4, g6 and some other lesser known cards), nowadays the 3 in 1 (source released early and then adapted means other "gba" expansions face an uphill struggle). DLDI (and the moonshell concept it evolved from) has leveled that field though.
eGladiator – Moderator and Reviewer at Elotrolado.net
1. It depends if you want GBA support or not. If you want a complete flash-cart, to play both type of games, NDS and GBA, the answer is very simple, the M3 Perfect. It has great compatibilty with backups and homebrew and other interesting features like PDA or the Extend, the best media reproductor in NDS Scene.

Things change if you only wants a NDS flash-cart. In this case the CycloDS Evolution is the best slot1 solution I have ever seen. R4 and M3 Simply are great flash-carts, but the CycloDS Evolution has managed to be the first flash-cart with perfect compatibilty in the Download Play mode. In addition, the integration of cheat in the menu, the autopatch DLDI and its full tactile GUI makes it easy and very useful.[Grammatical mistakes corrected by request of eGladiator]

2. If the buyer is looking for a cheap and functional flash without the loss of great specifications, the serious and logical answer will be M3 Simply or R4DS.[Grammatical mistakes corrected by request of eGladiator]

3. I believe that a pioneering flash as no other was the NinjaDS. Its release was previous to the one of the DS-Xtreme, something that some seem to have forgotten. I consider that it opened the way that has taken months later for the rest of teams.

Perhaps their sales affected the support from their developers that the flash-cart deserves, but that doesn't change the fact that it was the first slot1 flash-cart.[Grammatical mistakes corrected by request of eGladiator]
Iwakura – Reviewer and Webmaster of FlashCartReviews.com
1.  From my experience, I'd have to say the CycloDS Evolution is the best. It already has nearly every single function promised by any company or manufacturer, and boasts new ones that no other company has shown consideration for. I've heard that some were defective, but I've also heard that the CycloDS Evolution dispatched replacements immediately and efficiently. So, on the technological front, they're the best. On the human side, they've also got great service.
2.  If you were really squeezed for money, I'd say the R4. With a dedicated team and a large gamut of functions, it rivals the CycloDS Evolution. The only set back is its build quality, and it doesn't promise new features. However, I would only suggest the R4 in serious money-saving circumstances. For the reassurance that your spring will not break and the R4 will not corrupt itself (as two of mine have), I would get the CycloDS Evolution. In the end, it may save more money.
3.  When slot-2 solutions were the only solution out, I'd say the G6 lite was the best. Mine worked flawlessly, with some of the features that many slot-1 cartridges still don't have today. I'd say the next major change was the R4; many once-slot 2 users changed, and the R4 became the Zeitgeist. With perfect Rom compatibility (at its time), along with a few download-play compatible games (which were unheard of!), it easily became the most wanted item in the market. Now, I think a new generation is approaching. I would like say its the CycloDS Evolution, but I think its too early to determine that. I've seen many companies making changes to keep up with the competition, and its inspiring to see. Whichever cartridge ends up being the best, all of them are showing significant progress.
six-five-two – Reviewer and Webmater of SixFiveTwo.com
1.  The R4DS is about the best flash card to buy due to cheat options, skinnable menus, soft-reset. It also has a built in Passme which helps for Slot-2 flashcarts aswell. However, I think the CycloDS will catch up when they enable the Real-Team Saving and Loading. I would like the R4 alot more if they had both real-team saving and loading and perhaps a new version with SDHC support... By the way, I own a M3 Simply, but the M3 Simply and the R4 are both the same...

2.  For the best price, the R4DS is still the best with cheat options, soft reset, skinnable menus, and good price. So this is still the same as #1.

3.  Once again, I think the R4DS is the best. Answer #1 gives the best explanation, like before... I think the CycloDS has some potential and may be better then the R4DS when they add more features.
Zombie_X – Reviewer at EvilGameNetwork.com
1.  CycloDS Evolution

2.  R4DS

3.  Hard to say but perhaps the EZIV Lite Deluxe, EZ-Flash Advance II
Psyfira – Member at GBATemp.net
1.  I think there's no such thing as "the best cart", a lot of it depends on the user and what you actually need it to do. Personally I don't need a lot of storage space, 512MB would be plenty for me so the built-in memory carts (DS-X, G6) aren't worth the money (and micro SD cards are dead cheap now anyway). I want something that'll last, so the R4/M3 spring issues put me off of those. I can handle technical stuff like faffing around with savefiles so an idiotproof out-of-the-box setup doesn't matter to me. Other people probably require different things, but the EZ-V does everything I need it to (and is worth a month of demolished fingernails )

2.  Buying from abroad: R4/M3. Good software support, affordable, okay if you're capable of handling the broken spring. The community must love it for a reason so the cheaper price probably makes it worth it.
Buying from UK: EZ-V if you know where to look TotalGBA's bundle deals are the same price as a UK R4 bundle.

3.  I don't know tbh [to be honest]. The R4 headlined the slot 1's with it's cheap kiddy-affordable price tag and it's reputation as "the people behind the M3s" but I don't think that's quite answers your question.
4saken – Member at GBATemp.net and Team Cyclops Forum
1.  I think the M3 Lite Perfect is just a simple, unified device which allows you to play both NDS and GBA with high compatibility, and it would be perfect as a slot 2 device if it wasn't so expensive.

2.  This is a no brainer. At 30 USD, you can't beat the R4.

3.  100% download compatibility is a first, it's unfortunately the casing took a step back to the early days of slot 1.
I'm not sure why I chose the G6, but it was probably the most popular built-in memory device, and it worked a charm too, so theres no easy feat in that.
kms – Member at GBATemp.net and SCDev.info
1.  At present the best carts is probably the cyclopsDS evolution, I have'nt the chance to test it out yet, it will cost too much to have the item sent to hong kong as there is no distributor and dealers in hong kong. at present it's the most full feature slot 1 cart on the market, since it's just released onto the market recently, there are still many bugs, but updates are coming up fast.

2.  I will consider the M3 simply, although the R4 is just the same thing, but in hong kong the M3 simply is cheaper, for my needs which are to play nds roms, M3 simply and R4 fits my needs, nothing like cheats, GBA support and even movies are of interest to me.

3.  I started to use nds with the supercard DS one and changed to the R4 and M3 simply, less problems and easy to use, not settings required for R4 and M3 simply when playing roms.

I highly recommend either the R4 and M3 simply if you are just after nds roms play, simply to use, cheap and high compatible rate for roms.
ahtin – Member at GBATemp.net
1. R4DS/M3DSS will be my choice becasue everytime their update give us surprise, I cant beleive a factory can get a non-stop developing for a market share which already over 70% (maybe 90%in china) in the scense, most of the factory will choose to selling a new product.

2. R4DS/M3DSS , lowest price at the market with lots of function.

3. For Slot 1 Side, Acekard bring us the first cart which do not need to convert clean rom but this is the only one feature for this card. G6DS is the first cart support download play as their selling point but its fail at the first public kernel, I have test some download play is work before the public kernel when I using factory kernel, this is a big mistake for them so that I have to kick them out this time. R4DS/M3DSS make a price drop at the market, it bring some important feature for us like soft reset, cheat code running without original cart..... etc, the most lovely feature for user is 512k save type for all game, we dont need to try and error before starting a new game, this is my choice for slot 1 side
For slot 2 side, M3CF will be my choose for the whole question, for running backup game for general user, this is the only choice for backup solution, NDS Dumper V1.3 or WRG Dumper V.14 need both GBA cart and M2/M3CF, M3CF come with dumper program with their developer too. They have their own PDA system, the first chinese PDA system and the first chinese dictionary help lots of chinese student so much. Multimedia feature also is the best points for chooseing M3CF. In China, student like to using their DS for Gameing, Reading and enjoy the Multimedia features because most of them have not got their own Computer in their high school or Unviersity HALL.

h8uthemost – Member at GBATemp.net, SCDev.info and Team Cyclops Forum
1. Currently, in my opinion, the G6 Real and CycloDS are definitely the two top slot 1's to have. Without a doubt.

But taking into consideration the support TeamCyclops is giving their cart, compared to the amount of support the G6 Team is giving theirs, the CycloDS Evolution is the clear winner between the two. Now granted...it could because the G6 team is getting ready for their release of their 16G G6 Real on the 12th of this month, but...at the very least they could have done, was posted a message on their site, explaining that this is the reason the new firmware hasn't been released. I mean come on, keep your fucking customers informed.

 TeamCyclops has kept us posted the whole time about upcoming features and when we could be expecting the next firmware. Now if the G6 Real would give us a new firmware, that fixed the touch screen calibration, has the DLDI auto patcher in it, and gave us the 100% download play compatibility that we were promised, then I just might have to go with the G6 Real. I really like this cart, its menu, and its features. It's a great cart.

But definitely, right now, the CycloDS Evolution is the best flash cart to buy without take the price into consideration.

2. The answer to this question I definitely have to give to the R4.

You can get an R4+1GB Kingston Japan from DealExtreme for something like $43, shipped. And that is cheaper then about any other flash cart. And that's including a 1GB microsd. The R4 really is a great cart. It may not have all the features that some others have, but that certainly doesn't make it bad. The R4 gets supported really well. Every feature this cart does have, works great. There's a huge fan base for this cart, so I believe support will continue for it for a very long time. There are no bugs, that I can notice, with this cart or its GUI.  And with the right microsd, every game run flawlessly. So all in all, that is very impressive for the price this cart is sold for. If it had a few other features that the other two carts I mentioned has, then this would probably be the top slot 1, in my opinion.

So the R4 is definitely the best flash cart to buy while considering price.

3. I'm not the best person to answer this question. I got into the flash cart scene a few months before the slot 1's started rolling out(I think the DS-X was the first one). So, I haven't been using DS/GBA flash carts since they first came out.

But...if I had to guess, I think the cart that changed the scene with its features, would have to be the first cart that allowed both DS and GBA games to be playable on it. So whatever the first slot 2 to do this(Supercard maybe?), would have to be my pick.

And as for the one that was the best cart of its time, I'm going to have to go ahead and go with the slot 2 Supercards. It seems like everyone and their mother has/had one of these. They were very popular, and very well supported. So the Supercards get my vote for this question.
chuckstudios – Member at GBATemp.net
1.  Without considering price, CycloDS Evolution. It has basically the same features as R4 but has some nice things that R4 doesn't. Some of those include multilanguage in the menu, slow motion mode (which I have a strong feeling is just a bunch of NOPs added with the cheat engine), and SDHC support.

2.  With price consideration, R4DS. It is incredibly easy to use, and has good features. Cheat support, soft reset, and automatic DLDI patching are among its strong points.

3.  The most legendary cart, in my opinion, is the M3 Perfect. The thing suffered no slowdowns in GBA (unlike SuperCard), had near perfect NDS compatibility, and decent homebrew compatibility in pre-DLDI days. The built in features were always cool too, especially before MoonShell became so good. Having built in music and video is nice