Oh look, Ghost Recon Future Soldier has a 4-player co-op survival mode. There was a time when the knowledge of horde-mode style multiplayer really excited me, but it's been run into the ground at this point. Surprisingly, Ghost Recon's Guerilla Mode has managed to pique my interest despite the sea of mind-numbing carbon copies it's swimming in.
There isn't one thing in particular that stands out as different or better, but rather, the attitude they seem to have going into it. I get the feeling that they're making a real effort to push that game mode forward and I can definitely appreciated that.