I'm pretty enthusiastic about this one. A lot has to happen to bring about the downfall of mankind and have all the people become transhuman experiments or to just become so much meat. Morever, it takes a lot of skill to make it mean something, and the author has an uphill battle. 
 Think War of the Worlds or any number of branching sequels by various authors and you'll know what I mean. It's hard to write a short novel and have this much scope, but Wilson manages to write some really memorable characters. A little girl with robot eyes being a superhero of the resistance? Matilda, you're awesome. 9O2? A freeborn robot and free of the life-obsessed monstrosity of version 14? Brilliant. 
 Best of all, I love to see the downfall of humanity, the concentration camps, the modifications on both sides of the human camp, whether forced or forced-by-necessity, just to keep up with the hell of a long and nasty conflict. 
 Gray Horse? OMG. I love these guys. It's a long, hard, war, and they keep modding themselves to keep up with the horror of it. I loved seeing them lose more and more of what we'd deem humanity, but to them are just the necessities of winning the battle for the whole future of mankind. There's practically no one left at that point. It's more than dire. It's hell on earth. 
 A lot of people liken then is to World War Z and there are some similarities, of course, but in a few significant ways, I liked this better. Robopocalypse isn't an epistolary novel, for one. It's a straight story with some epistolary moments, excerpts, and recountings. The characters we stay with are with us for very good story progression reasons, and the ones who get the most face-time are brilliant heroes in their own right. 
 Even so, this is, however, still a relatively short novel with many players, including our big bad AI, and we have a pretty nearly unlimited view of the entire stage of the war. I'm not going to say that I don't see where it might have had some improvements, but on the whole, I was freakishly impressed and thrilled by the scope, the epic horror of it, and the fact that it fired my imagination and it kept me enthralled by its sheer panoramic action. 
 Hats off. This is some serious SF beauty here, doing a much better job than the terminator movies at drawing us in with the scope or the importance, minus all the time travel crap. This is the end of the world, folks. :)