I have enjoyed this game so far. Haven't tried the campaign but the online mulitplayer is good.
Never had any lagging problems so far so can't comment on that. I did notice that there was a lot of spy planes in each match but as people have said earlier this is because of the low ranking. Once peoples rankings are up then spy planes will be less frequent.
The graphics are too bad, seen better but seen worse. I'm more into the game play so the graphics aren't really a factor for me.
Spawning is a bit crazy. You sometimes respawn right in front of the enemy for them to pop you off without you even realising what the hell is going on.
The maps are new so more things to explore.
Zombies is awesome. New things to do, new zombies to kill and even some zombie nutter running round nicking your guns. Its funny, scary and very entertaining.
Well thats my opinion done