Well, I should first say that I own a copy of Data Persistence with Hibernate (DPWH), and I refer to it often. DPWH is really the reference manual for Hibernate, and I think we're very lucky to have such a complete reference manual available to us. Similarly, the Caveat Emptor application that is referenced both on the website you list, and in the DPWH book, is an excellent example of a production type system.
But having said that, I think there's a real need for a book that provides very simple examples and explanations. For example, in my book, you can find very simple examples of one-to-one, one-to-many, many-to-many and inheritance mappings with a corresponding runnable class that will allow you to run and test these mappings without the need for a web, ejb or Spring container. That way people can test very simple examples, and then customize them for their own purposes. In my opinion, this is the best way to learn.
When I first started to learn Hibernate, I found it frustrating. I knew Hibernate could do some awesome things, but I just couldn't find a resource that helped me get up and running quickly, with some simple and straight forward examples that would help me understand how Hibernate worked, and what was going on behind the scenes. And from what I read from reviews on other books on Amazon, it seemed to me that I wasn't alone in my frustration. This book is really a response to that feeling. My goal is to get people up and running with Hibernate quickly, and help them leverage this great data persistence mechanism.
Furthermore, my book is very focussed in its content. While DPWH covers mappings and annotations, and a little bit of Spring, and even JBoss Seam, my book really just focuses on one objective, and that's teaching you how to use Hibernate. And it has been my experience that when people really, really understand how Hibernate works, and how it should be used, integrating Hibernate into Seam, JSF, Spring and any other application out there, integration becomes easy, because you really understand what is going on.