Well, I found it was OK, but it didn't go into the really DEEP issues. I bought this book because I had a problem and needed some ideas to help solve it. The book did not help much. It is not a book really for people who have been sysadmins for many years, since this will all probably be second nature to you anyway.
Anything you don't normally need to do is not really covered. How do you disable NIS, or NFS? What are the file locations? what about on AIX or OSF/1? If you cannot use the standard configuration tools, what files do you need to manually edit to get it all up and working? What's the syntax?
That said, as a primer to get you up and running with NIS and NFS, it's good, and goes into some detail on related issues as well. It also looks like it'll be a useful resource for administrating them under less extreme circumstances than I've recently been experiencing.
It's also quite readable. A little dry, but you expect that in a computer book. The tone is conversational rather than tutorial, which helps.
However, the book seems to waver between being a reference and a tutorial, and is not sure which to be.
Not the most essential of my O'Reilly books, but I'll certainly be reserving it a place on my desk.