I manage a software team and have read this book cover-to-cover in order to study Puppet for our team's use on a daily basis.
Despite step-by-step instructions for the initial installation, I needed some tinkering since different OSs have slightly different distributions, but once I had a server and agent running on two different VMs (Ubuntu) - there was an "Aha!" moment when the agent had emacs automatically installed on it! Getting past the initial installation phase allowed me to really enjoy the rest of the book as well as enjoy Puppet itself.
Puppet is not trivial, but the book covers its concepts very clearly and one "gets" it quite early on (especially if you get your hands dirty and follow along the examples).
The book then expertly guides the reader to its "pro" section detailing use of Puppet with configuration management tools such as git and db-based storage.
It then goes on to detail how to use AMQ with Puppet for scaling. I doubt I will use such a robust configuration, but was thrilled to see how flexible and extensible Puppet is by use of load-balancers and integration with Apache/Passenger.
Overall, the book is well written, and I would highly recommend it as a *text book* for Puppet. This is a readable text book on the subject - not a reference manual, although it has countless links to the reference manuals.
I always wanted to learn Puppet, and this book certainly is the one to read if you're dealing with configuration management whether as a developer or a DevOps person.