Im liking opp's more than zombies, although i did like zombie's i just didnt like how when you where taken out, you started with the pistol again and had no chance of killing any of them with it.

Opp's could do with a litle twke like making the time inbetwine wave's to 60 sec for single play and have the option for more players on co-op and to have more that one perk.

4 players, Pack a punch, Specially designed maps, 3D, and the mystery box I think is better.

good question but i have to say it's difficult to compare; beside of the fact that they're both 'FPS-survival' i can only sum up some good and bad points:

ZOMBIES:

+ powerups

+ mystery box

+ trains

- looooooooooong (co-op lvl 60 + takes 8 hours)

- boring after round 30

SPECOPS

+ airstrikes

+ combos

+ fast round-up

- it's not zombies

I'm zombies all the way. Was hooked the second it loaded. Matter of fact loved it so much I have all the maps from nachet der untoten to moon.