This book is hugely overrated. It's not bad at all, but I don't think it holds a candle to World War Z, a much better book by Brooks.
There are two main problems with this book:
1. The science. If you don't know your science, don't try to write about it. I can forgive ignorance if you aren't making a point of the science, but if you are, at least try to get it right. This is, of course, so much worse with biology for me since I'm a biologist, but it was so bad I kept coming back to being annoyed by it.
2. Too much flashy, console-gaming violence and not enough with the practicalities.
All in all, it is a fun little book, and I'll be quite happy to pull out a couple of the arguments in the book with the people that I generally have zombie-survival-strategies arguments with.