I've been using Toon Link almost exclusively so far in Adventure Mode, though last night I unlocked Linkle and immediately rupee'd her up to 13 (my current highest). My only gripe so far is that giving Toon Link a basic bottle requires a material I haven't found at all, so everyone but him has some badges unlocked.
I really should hunker down and clear more Legend Mode.
Edit: Graphics look like what I expected a Dynasty Warriors game on a handheld to look like: They're okay, but everything has to be kind of fuzzy due to the scale and speed of the action. The most noticeable thing is the pop-up of new enemies, since the 3DS obviously can't render hundreds of things on screen at once. It's a lot of "kill this cluster of 10-20 guys, and then wait a second for corpse despawn for new enemies pop in."