First, the book is only 363 pages long, not 560 as identified in the Amazon description. So in my opinion a little over priced for the content.
Having said that, I found the book contained a lot of information that I wish had been in Server Essentials. Of course, considering that these are geared towards the Apple exams I suppose you have to give them some leeway.
As I am in the process of planning an OS 10.5 Server upgrade, this book has been helpful. I'm still hoping that someone will write more about Print Queue Management in OS 10.5. If you're looking for more info on that subject, you won't find it in here nor in Server Essentials.
Overall, if you're new to supporting OS 10.5 Server or migrating from 10.4 to 10.5, then this book has some helpful information - but maybe you can get lucky and find it at a discounted price. I don't feel it's really worth $65 but I'd consider $35 a fair deal.