One of the greatest Xbox Live game of all-time.
The multiplayer modes of MechAssault 2 are where this game really shines. Up to 12 players can compete in Destruction, Team Destruction, Capture the Flag, Base War (destroy the other team's base to win), Not It! (kill the person who's It to score points), Check It! (Hack into bases to capture them, then hold them), and Snatch It! (retrieve data cores and return them to your base). Team Destruction and Destruction are the most frequently played on Xbox Live--you just can't beat a classic.
My one issue with the game is the single-player mode. It's short, and it's fairly easy, though the "Elite" difficulty may present difficulties to anyone who hasn't played on Xbox Live and honed their skills for a few months.
Basic controls are very simple to learn. Advanced techniques such as wallwalking, however, can take hours to master. Obviously the more you play the better you get at aiming and thinking strategically also.
In short: If you have Xbox Live, get this game! If not it may be best to skip it unless you're a hardcore BattleTech fan. I've played MechAssault 2 online almost every day since it came out, over a year ago. Talk about replay value!