It's like MW2, only better!
I can't speak for the single-player mode because I haven't tried it yet and it will most likely be a while before I even get in the mood to want to try it. The multiplayer is where I spend my time.
Finding a game was quick and easy, as its for the PC, it appears we have lost dedicated servers to some degree, but there is a dedicated server option within the game, though I haven't tried it yet. You can actually team up with friends like in MW2 (but unlike the PC version of Black Ops) which is a relief.
Graphics are crisp and updated, they may not look like BF3, but the game play is far superior in my opinion. Hit detection seems spot on, knifing seems a bit off still but I haven't played a CoD game that ever got the knifing mechanics down right. The game can seem confusing and overwhelming at first glance, and rightfully so actually. There is so much going on it's hard to keep track of everything in your first few matches. I am still confused by a few things but by tonight I'll have figured everything out. The maps seem like rehashed MW2 maps but they are still very good. They have some funky guns in this game, but that should keep things interesting.
All in all after only 90 minutes of game time, I am hooked. I am writing this review at work right now kicking myself for not calling out. Fans of MW2 will love this game, and those who hated MW2 may actually enjoy the feel of this game a little bit better.