I've been playing it for about a week now, now that I got it installed, and I'm glad I did. I'm really enjoying it. (It really, really, feels like Diablo 2.... if Diablo 2 had a way to reset your skill points so you weren't hosed if you make one mistake early on) Started with Rocket Raccoon, who I've gotten to 26, and unlocked Squirrel Girl, who's level 10.
I decided I'd rather play with characters I like than with the ones who are the current FotM, so I didn't do much reading up on the mix/max potential of any of the characters. I just enjoyed Rocket's summon-based playstyle (so I uncapped him first), and I took SG on general principles. I'll probably get Storm or Thing next, but that's some ways away, and these two should hold me for quite a while.