I only played Multiplayer and Zombies

Likes and Dislikes so far

Likes:
Faster Player Movement
Frame-rate is steady
Gun customization system makes you chose how to spend your points
Reduced Gun kickback
Servers are pretty fast, I only had 1 game with lag so far.
More Killstreak Rewards
Some interactive options on maps that allow you to get to different places that you couldn't normally just walk to.
No Nukes

Dislikes:
Graphics (HUD looks like a downgrade,Emblems and Titles look dated, Loading screens also look pretty bland)
The knife is still gay
You cant hide as well within the environment (snipers are super exposed)
Player models don't look so hot



I like this version, but I still give an edge to MW2
This definitely feels different but overall it seems like a slight step back at least as far multiplayer goes.