That was tough........ I chose Ninja Ds because of the nice interface and slot one capability. I beleave you get to use the actual rom so Download play works for every game. I wanted to choose DS-X because its the same thing and actually beats the Ninja Ds with it's drag-and drop capabilities. I didn't pick it because some of my favorite games don't work on it...... I wanted to choose supercard because I have it.....but the Ds download doesn't make it. Also the use of a passme isn't bad but its just a little peeve that barely bothers me........