I really enjoyed the book myself.
The chapter on netflow was informative and insightful. Especially given the amount of emphasis security practitioners are putting on the technology (thankfully to netflow gurus like jose nazario -- conficker finder).
I also really enjoyed the physical security chapter. Rarely do technical books dive into that topic which is unfortunate since physical breaches are the easiest!
The included WAF chapter is essential these days. Typical signature based NIDS are too easy to evade.
I give it 4 out of 5 stars...