I have both Pokémon Dash and Ultimate Spiderman and they work flawlessly with the Supercard Mini-SD! IE: We already have an update for our patcher that fixes all games up to 0496 to bad you don't with your M3! Try saving on Rockman ZX yet? LOL, oh wait... you can't! Supercard updates its software and firmware more than any other company and any one will agree to that as its even on the Supercard reviews! Since Supercard's release they have come along way and now have the best DS game support of any flash cart. Every time about 3 games are released a new patcher version comes out! If you're going to be using your DS to play just DS games then the Supercard is the way to go as its cheaper, has better game support, and is the smallest and looks the best in your DS!
http://gbatemp.net/index.php?showtopic=32151
As for Supercard vs M3 in terms of performance there really is no difference. Games run just as they would as if you had the original cart in the system as long as you have good media. You'll need a fast Mini-SD or SD card as you don't want to have any problems loading games or getting a little slowdown. There is a compatibility chart for M3 and Supercard that has proven that cards with 60X or higher have NO slowdown what-so-ever. IE: In my Animal Crossing game I have a bit of slowdown in my menus, but not in-game, with my Sandisk 2GB Mini-SD card. I just bought an 2gb ATP ProMax 150x Mini-SD and the slowdown is now gone, not to mention the Castlevania test works 5 of 5 stars without a bit of problems in the video! Before with the Sandisk all it would display is frames with sound. So your media will make or break your Supercard or M3.
With the Supercard Mini-SD, Passcard3/Superkey, ATP 1GB ProMax 150X or Ritek 1GB 150X Mini-SD it will be exactly like you have the purchased game in your Nintendo DS slot! SDNewegg.com has a 1GB Ritek 150X which has been tested with both cards and runs games just like you had the cart in your system! The M3 does have better GBA game support but I don't play many GBA games and the ones I do work! It supports all the big names like Kingdom Hearts, GTA, Mario games, Metroid, etc...
http://www.newegg.com/Product/Product.asp?...N82E16820183183
It’s all up to size as well. The M3 is bigger and sticks out of even the DS Phat while the Supercard its flush like a GBA game! If you're going by looks then the Supercard wins hands down. If you have a DS Lite you can use the picture below to see how each flashcart will look like in your system and still the Supercard looks the best. Supercard and M3 also have new versions of their product coming out in the next couple of months that will sit flush with the DS Lite, or so M3 says. They also said the M3 "Lite" Mini-SD would sit flush with the DS Phat and you see how that turned out below.
Supercard Mini-SD
M3 "Lite" Mini-SD
M3 "Lite" SD
Passcard3
All flashcarts in the DS Lite (Notice the Supercard is the smallest!)
When you look at the above pictures you can tell that the Supercard Mini-SD is the best choice since it fits flush like a GBA game. It has the best DS game compatibility of any flash card on the market (just read the reviews) and is one of the cheapest! Together the Supercard Mini-SD and Passcard3 make you're DS a 50+ game playing machine! The M3 is also a good product and has better GBA support but not as good DS game support as the Supercard makers update their Firmware and Software more often than the M3 guys. The M3 products also all stick out of the DS like an eyesore. But if you don't mind that and want to use SD, Supercard also makes a Supercard SD which does stick out of the DS just like the M3 SD in the above pictures.
And as for the FAT issue both the Supercard SD and Mini-SD support media of 4GB and up. I have tested 4GB with my Supercard Mini-SD and some places sell a 4GB SD and Mini-SD card with Supercard.
I personally have a DS Phat, Supercard Mini-SD, Passcard3/Superkey, ATP 2GB ProMax 150X Mini-SD and wouldn't trade it for the world! I can play all my favorite GBA games, DS games, SNES games, NES games, GameBoy games, ,Sega Genesis games, Master System games, PC games, eBooks, homebrew games and apps, music, movies, and more for FREE! And whatever size flash card you have is the amount of memory you have! Right now SD and Mini-SD goes to 4GB+! I have 2GB and I can fit everything on it! With me it was the fact that the Supercard is smaller and has 100% DS game support that made me buy it over the M3.
With my Supercard Mini-SD, Passcard3/Superkey, ATP 2GB ProMax 150X Mini-SD in my DS Phat you can't even tell that I am running roms unless you first turn on my system and look at over 60+ games in my list! You pick the game you want and start playing and once that game starts instantly you will think that you bought the game and won't be able to tell different; And better yet neither will others!
FifthE1ement