Decent DLC, but not astounding.
Carnival - 8/10. Very good for local/splitscreen/LAN party games... as long as the radar is turned on. On multiplayer, this isn't the best map in the game, but it isn't too bad either. This is one of those maps where you can use just about any ridiculous gun you can think of and still survive if you're good at this game, and then play again in a different lobby with your favorite gun and die. This is a pretty decent map, but not my favorite for sure.
Trailer Park - 7/10. Good in multiplayer. Fun map overall. There isn't much to say about it, because there isn't too much to it. There is one thing I love - there really isn't any way to get higher than your enemy and snipe. All in all very good SMG/CQC map.
Fuel - 4/10. Sucks for everything but Search and Destroy, but it is VERY good for S&D. There are a few completely annoying glitches (you can get inside of rocks, LOL)
Vacant - 5/10 Sucks even more than in COD4. It's a mix of noob toobers, RPD campers, and akimbo'd shotgun noobs. It's not a good map.
Strike - 10/10. I HATED this map on COD4 for a lot of reasons, but it's back, and it's actually really, really good. The visuals have been revamped to be a little more greenish. Good overall map, not really anything I can complain about.