I played a wee bit last night after work (also after half killing my left arm with another hobby). As someone on another forum I frequent aptly said, it is essentially "MW2 with more recoil".
I do, however, like the addition of lesser known, but dear to my heart weapons, like the FN5-7, P99 and the return of the G36c and full-stock MP5! It's nice to see that Soap's impressive mohawk is more solid than it was in MW2 too. Sound design is excellent, and the tweaks in terms of weapon design are a great update.
I like it.