This game is every bit as good as it is hyped to be. Buy it as soon as you can if you are a fan of shooters.
The single player is good. Excellent is probably a better word. The problem is that I dont get much time to play it because the mutiplayer is so amazing. Ive clocked in a stupid amount of hours cappin fools in the head and anywhere else i can reach. The reason everyone plays so much is the level system. Much like gamespot, you go up in levels the more you play the game (10 points to kill someone etc...)
Unlike gamespot, this actually means something. You unlock more guns and perks, not to mention you look like a badass the higher your level is. I am currently level 46. There are only 55 levels but as you would expect, they get harder and harder to get to the next one.
Go and buy this game now if you have Xbox live. If not, go and buy the game aswell as xbox live. You are really missing out if you dont.