I would give it a 7/10.
Gameplay - 6/10 - The Gameplay ways pretty good, it's just that it got very repetitive after the 100th kill. It felt like you did the same thing over and over again. The good about it was the ammount of powers you can do with each of the X-men and Brotherhood.
Graphics - 7/10 - The Rendered cutscenes looked very very good, but the gameplay graphics looked very bad. But, I'm a sucker for the Cartoonish look. It was okay, but sometimes looks horrid.
Story - 9/10 - I don't care what anyone says, but to lead a force of X-men and Brotherhood members against the greatest Marvel superhero villian in a clash of the titans is fun!
Sound - 7/10 - Some of the sounds sounded weird, and reused too often. But the voices (and voice-copies) of the superheroes were fun to hear.
Lasting Appeal - 5/10 - There isn't a whole lot to do after you beat the game really, except play it again. Although playing as Iron Man was very fun.
The game was pretty good, but didn't leave me satisfied all that much.
Wake up. You were dreaming. What's your name?