While this is an informative book, especially concerning Microsoft networking utilities and features, there were definitely some areas on the Network+ 2009 N10-004 test (just took it today, and passed, but not as well as I would have liked) that were not well covered in this book. The areas that could definitely use more attention were CIDR-based sub-netting and physical facility equipment and tools. There was a lot of emphasis on troubleshooting scenarios as well. While the book (content/quizzes/test) focuses many questions around Microsoft tools/utilities, I experienced next to no Microsoft-centric questions on the actual test. (The test is actually very vendor neutral)
I realize it is not easy to create a test prep book like this, and I appreciate authors like Glen providing these resources. But at the same time, it is hard for any book to provide all possible knowledge needed for a test like this.