In actuality The SuperCard DSTwo is ranked the best but the most expensive Acekard2i is Ranked #2 and at a reasonable price.It's all up to you though.
The DSTwo is okay. The GBA emulation is only sub-par right now, and it already had to have a firmware update once. It is only ranked #1 based on their promises so far, not so much experience. It can't truly be considered the best after less then a month. I personally would go with an Acekard2i + EZ Flash 3in1 if you have a DSlite or a DS Phat. Not only is it cheaper, but it will do GBA emulation much better. The AKAIO firmware for the Acekard2i also makes it work perfectly with every release right now. If you have a DSi though and want GBA emulation, the Supercard DSTwo is pretty much your only option.
/facepalm Having a DS phat, you really should have gone with the Acekard2i + EZ Flash 3in1. The Supercard DSTwo is still working off of promises, there is still no proof it is the best cart. The only reason it is rated so highly is because people go "Oh, look, Slot 1 GBA emulation! I don't care how bad it is, I'm buying this cart because of that!". The cart hasn't even been out for a month. I personally wouldn't purchase a new flash cart that promised so much on the pre-release until it proved it could deliver.
so what i have choose supercard two or Acekard2i some people say get supercard dstwo and other Acekard2i ????????