I am a system administrator, and I have recently taken the 70-291 exam. Now these days there's a lot of practical simulation oriented questions, and I found that this book's step-by-step exercises for various technologies to be immensely useful. And predominantly for this reason, I am rather well disposed towards this book.
There was a lot of emphasis on TCP/IP math, but in actual practice, at least for my exam, I never had any specific math question. There was only one DHCP question that did require one to know how many hosts a given the bit-mask would allow for, and also the corresponding valid IP ranges. So I am grateful that I pushed myself to get into the mindset transforming bit-masks into quantity of sub-nets & hosts and also valid IP ranges, or else I might have missed that question (or maybe I did :)...
Overall, I think reading the text material and doing the exercises with and actual Windows 2003 Server and Windows clients, will prepare you for the exam.
In combining through the first two chapters, I did found some potential mistakes:
(1) In instructing on sub-netting on page 24, they say to "subtract 2 subnets", essentially the first and last subnets. But this conflicts with the self test answer #3 (page 37), which doesn't subtract 2 subnets. From this, I couldn't understand whether the instruction or the self-test was correct, which is disturbing (especially before the exam)
(2) The self test answer to #14 (page 100) states that "you must know the name and MAC address of the DHCP client." However, in real world application, I found this not to be the case. You can use whatever for "Reservation Name", and in fact DHCP service has no support for using the client name (Linux/Unix DHCP services can utilize that with ISC DHCP server). This makes me wonder about the author's in-depth knowledge at least in this area.
I didn't get enough to comb through this tomb completely, but I will delve deeper. Despite this, this is a worthwhile starting point.