Ok, got the game at midnight last night, haven't stopped playing since right now-yes, I brought my Xbox to school.
Good: amazing use of bump-and-normal mapping, AI spot on for enemies, weapons are relativly balanced, Multiplayer is more addictive than crack(especially online), boarding completly craps all over GTA,story is immensive(I wasn't bummed with the ending at all)
Bad: Texture pop-up in cutscenes(pain in the ass), your AI buddies aren't that good of drivers, campaign is a little short, the game ends.
I highly recommend this game to anyone who has an Xbox, loves FPS, and has many friends. It also wouldn't hurt to buy the Official Guide from Piggyback, the art in it is absolutley phenominal, as well as the Official Soundtrack(IMO, the best game score ever. Yes, even over Final Fantasy).