User blog comment:Drkdragonz66/Modern Warfare 3 interview: Robert Bowling talks about Spec Ops Survival/@comment-4243347-20110814022810

Seriously, I think both survival and zombies will be good, and neither is better than the other. Why? Well, I think they are quite different. Zombies can't fire back with weapons, but they have a ton of health, can move very fast latter on, and take two hits to kill you. Survival is against a bunch of soldiers like in campaign with normal health, but thay have guns themselves. They have different styles to what you need to do to survive. Zombies is fun because you rely on luck to get good guns and you explore and experimant each time you play to find a better place to hold up in. Survival requires you to react to what the enemy sends at you, because there is a lot more variety to enemies, there's more stuff to use in your arsenal, and (hopefully) a round won't be the exact same on each playthrough. Basically both are really fun, but in their own different ways.