Well it's not your standard awesome set-piece blockbuster CoD singleplayer (which I love tbh). It's pretty much multiplayer matches (they're the same maps) with bots and some cutscenes in-between, although you can make it so the single player "missions" are played with and against real people which is fun although that pretty much just makes it a multplayer match. I wouldn't say it completely sucks balls but it's nothing great, not worth buying for single player alone.
Multiplayer is where the game is at.