Take it from somebody who has played the game, IW do it better than Treyarch. The single player is a trainwreck, but I haven't played a FPS in a while that wasn't this way. This game's multiplayer however shits all over Black Ops (and BF3, but that's because my comp is too **** to run it and I have only played the console version). And despite not being as cool (because of lack of zombies) Spec Ops Survival is more fun than the zombie mode in blops.
I'm glad the money system from blops is gone, I felt that I didn't have to earn anything in the game. Money wasn't hard to come by and I never didn't have enough money to buy what I wanted. It was too easy and there was a lack of accomplishment. This is the same for the emblems and callsigns, I like being able to make my own emblem but again there was no accomplishment in the things and I got pretty sick of seeing cock and balls everytime I got killed.
The levels are much better designed than previous games. They're not very big, but they're designed with a bigger focus on vertical changes. They could have used a little more variety, but that's more of a superficial gripe than anything. The new gun upgrades are pretty cool and upgrading them isn't difficult (it's just kills and headshots), but reaching levels to unlock sights and things is still more rewarding than just buying them. The pointstreaks are pretty cool too, and they can be tied to each class. It does suck that they have still included the point stacking, but hey it's hardly that unbalanced if I can exploit it too. Also it's pretty lol that they still included a nuke like streak in the MOAB.
All in all, it's fun. Not too different, just refined. I can't think of anything they took out of blops that I miss, and all the addition seems pretty cool and interesting, even if I haven't had too much time to mess around with it all.