Very Immersive storyline.
A new addition to the game is"spec ops" in which you can take part in a series of separate mission either on your own, split screen or online, to earn stars. A higher difficulty leads to more stars. This is a great addition to the game and if you're not so interested in the muliplayer, it adds alot to the single player and is great for split screen, which games these days tend to lack.
As for Online multiplayer, there is a lot more content e.g Kill/death streaks, callsigns etc and more ranks making it more fun and adictive, but it's still very familiar to the previous game, but in my opinion, Modern Warfare had better maps.
Summary:
Good:
Great multiplayer
Great story (prefered MW though)
Great Gameplay
Great Characters
Bad:
Maps could be better
Chavs...