From what i read Supercard is pretty good, SDHC support etc. but i requires SDHC card because on normal SD loading will take ages, compared to 2-3 seconds on Acekard2i using SD card(which is cheaper too, and offers same support). Try playing ye old DooM on your DS - its awesome. there is heretic port, hexen port, Duke Nukem port and lots of useful stuff.