Since this is a multi-console game, I thought it'd be appropriate here.
My team was the Fantastic 4: Mr. Fantastic, Invisible Woman, Human Torch, and The Thing.
Not only do you get a bonus, but each one of them were unique and had something different to offer.
Human Torch could fly and had awesome attacks, The Thing had brute strength, Mr. Fantastic had some unique attacks (I'm sure there was something else, I just can't remember), and Invisible Woman was great for defense.
I'm just using the starting four that they give me. Captian America, Spider Man, Wolverine, and Thor. I did try out the Fantastic Four one time. I liked it but I just went back to the original. I might change it up though.
I really didn't like the bonuses that they gave for the different teams (Fantastic 4, X-Men, Avengers, etc.)
I wanted to mix up characters, but then I wanted to get the bonuses at the same time.
Someone else here had to have played M:UA.
I won it on launch day, scored it 8/10. Great game...
...Now, I've had a few teams, Nightcrawler, Venom, Cyclops, and Doom was a fun one, though. On Wii, I liked Deadpool, Wolverine, Torch, and Storm...it balances well.