COD4 because it came first. What I mean is that COD:WaW is basically a WWII setting of COD4... with a flamethrower. Most I can say is; I just wish I could shoot zombies. Even wishing that I could just murder zombies like Hell, I still don't think it's worth my money. Now I hear there's a second Modern Warfare coming out, that I will buy...most likely.