Unfortunately, I have not gotten into the Beta for this, but the one person who I know that has, says it is freaking awesome.
He said that it is basically like D3 meets Superheroes which sorta meets LoL.
The game play is like Diablo. Only with superheroes.
It is actually a free to play game, but you have to buy additional characters/costumes if you want them.
I don't know who you start with, but when i try out the game, the first name on my list will be The Incredible Hulk.
If you get a chance, check out the gameplay trailers and maybe even sign up on their site.