The first few chapters and examples are very well explained. The book acts as a nice introduction to web development as well as the play framework. However the advanced chapters are poorly written; the asynchronous web development chapter in particular. Explanation of the example code, and play Akka helpers is weak. In general, the on-line play documentation was much more useful than this book.
This book really helped me to get started with the Play! Framework. It helps you discover the framework in a way that the docs don't. The book is a well-constructed tutorial that takes you through all the steps necessary to create a fully functional web application.
Cons: It covers Ebean, which is now being phased out in favor of JPA. It does cover some JPA, but assumes you already know how to use it. Some chapters are poorly written or unnecessary (chapter 4, for example). Some sections also seem out of place and break the natural flow of the book (the sections Interceptors and About scopes in particular, they'd better be moved).
All in all, this has been a very helpful book for me, I would definitely recommend it!