The AK2 is a great card and does about everything the RPG can do at only a fraction of the price.
Ive got both. i started with an ak2 and then went on to get an RPG.
For me, its RPG all the way, cuz i really dig the 1gig of on-board NAND, which almost NEVER has any issues running Roms, and the cut/copy/paste feature is more useful than with ak2 for on-the-fly file transfers and such (i've got friends and fam with ak2s and NO pc pirate skills), plus the card is built well and is super sturdy, ...but thats just my preference.
So, yeah....stuff and things.