Borrowed my friend's 360 and completed the game in 2 days flat, I must say this game is good, but it could have been more. I find the last few plot arc to be pretty good and dramatic, not to spoil anyone here. Personally, I wish they develop more materials for each character (I could have missed a lot while rushing through the game). The main story arc could have also been more elaborate, it kinda of feels like they were rushing for release.
If not for the fact that I don't have a 360, I would have bought the game immediately. All I can do now is hope that they will be releasing a version for PC. I'm certainly going to play it a second time if they ever release it on another platform.
EDIT:
I agree with the posters, the AI is stupid, I find myself screaming "Don't cross my line of fire!" at them all the time or "Why the hell are you just shooting at walls!"
The inventory is crap as well, I spend way too much time cycling through my inventory and trashing stuff, and they throw an absurd amount of gears at you.
I pick an infiltrator, specializing in sniper rifle (which is stupid but too late, guess I suffered from sniper-assassin complex)