Though I haven't ordered the book, my understanding is that most of what is in the test prep books is available online through forums and other resources.. the problem is finding and organizing the info. The books (whether Captain Bob's or Don McNea's) put it all in one place.
Bigger departments change up their hiring processes and testing procedures enough that to order one of the packages geared specifically toward a certain city seems less useful than a general prep book.. but then I guess it depends on how much money you have to spend on it.
I can absolutely recommend a book called "How to Smoke Your FireFighter Interview" by Paul Lepore. The stuff in there has definitely helped me be better prepared for the questions being asked in interviews around here. However, it doesn't do much for written exams.. except that departments appear to be increasing their use of the situational type questions on written tests that happen to be the focus of this particular book.
Good luck with the hunt,