As a long time fan of Chris Diaz's work, I must say this is among the best he's done. I hope to see more books from Diaz as quickly as possible. If you want to run a Post-Apocalyptic or modern/near future game, this book is for you. He's evolved 4e into something much more usable, and if you're a follower of his work, you'll note that WotC have taken more than one idea from him.
[5 of 5 Stars!]