Treyarch just sucks. The aiming, the AI, getting stuck on stuff, all sorts of crap in single player. They just used COD and COD2's success and raped our wallets for $50.
Multi, wasn't terrible, my buddy ran his own server for us and we were all local, so that helped.
I'll probably play it, once I go back and beat COD2 and COD3 again for those achievements...