Black Ops, Nazi Zombies?

I'm trying to decide if I should buy Black Ops for PC. The only thing is, I'd only buy it for Zombies. The multiplayer sucks. Game play is way too slow and what not. Anyways, I can't decide if it's really worth $52 for Zombies. I'm not sure how fast you get bored of it, or how entertaining it is. If I don't get it I'll just save my money for BF3 or MW3.