The author does a good job of applying well-known and not so well-known psychological principles to game character development. I was surprised to find that the book is mostly substance and doesn't have a lot of fluff. There are interviews from game industry veterans at the end of each chapter which helps to provide more viewpoints on the information. I found the interview with the two japanese designers to be the most interesting.
I think the overall point of the book is to take more into account when designing characters. There are reasons behind every decision you make in anything you do. This book helps to uncover some of the psychology behind characters and their interactions.
With all of this in mind, I would have to say that I don't feel this book's $50 pricetag is completely justified by what I got out of it. The information for me wasn't completely eye-opening; and there's nothing that specifically sticks to mind after having read it that would change my approach to characters a whole lot(other than perhaps their interactions).
The dvd included with the book adds very little to the subject matter; it is nothing but a bunch of low-quality cutscenes from video games. I expected the dvd to have interviews, supplemental reading material, or at least the author commenting on the cutscenes chosen. Unfortunately none of that is included.
The quality of the book physically is very high; it is printed on extremely high quality paper(thermal paper I'm guessing) which seems like it would be very resistant to stains or water damage.
Overall this book is a worthy read. If the price was closer to the $25 mark or the dvd included more worthwhile material I would definitely rate it a lot higher.