This story is a blend of The Watchmen and World War Z. In other words, super-heroes meet zombies. In a way, that's already been done in the Marvel universe. But there, the heroes became ultra-powerful, sentient zombies themselves. In this book zombies are (for the most part) the boring, shuffling, Romero zombies. Although some former super-heroes (and villains?) have been turned, they are not sentient and so not very dangerous. What makes this book work?
First, the writing is good. Not great, but definitely easy to read and suitable to the material at hand. It's got lots of action and the super-heroes are interesting. Each gets their own back story, and none are so powerful that they completely dominate the story (no Superman here). There are some rough similarities in terms of powers etc. with existing super heroes, but they are individual enough to be unique rather than clones (so this isn't Justice League vs. Zombies).
Second, the second is good. The heroes have taken over a former Hollywood studio thanks to its large walls and significant supplies. A few hundred humans live with them in a combination of trust, fear, and jealousy. The latter elements are what reminded me of The Watchmen, and introduce ethical issues that give this book a little more weight than it would otherwise have. What are the obligations of super heroes to "normal" people? What's justifiable in an apocalypse? What morals slip or die as a result? This made for some of the better reading.
Finally, the foes are good. The heroes are not just up against regular zombies, but there's a couple worse ones and a whole lot of unfriendly humans to boot. That keeps things fresh and interesting. When combined with the back stories and the more cerebral plot issues, it makes for a fun bit of reading. As I said before, there's lots of action but the book is reasonable in the amount of gore it presents. This isn't a children's book, but it doesn't wallow in disgusting shock gore either.
So this is a good book. I didn't give it five stars mainly because I found it a little short. But if you really like zombie fiction, or super hero fiction, or just weird fun fiction, I think you'll like this book and I wouldn't argue strongly against giving it five stars. It's not that deep, nor is it classic writing for the ages, but it is a very fun way to spend a few hours. My strongest recommendation perhaps is that I've just order the sequel,
Ex-Patriots: A Novel by Peter Clines (April 23 2013), so these are heroes that I'm willing to pay money to keep reading about.