I'll have to check out the book.. I've been using Play for about 8 months now - I absolutely love it. After doing enterprise Java work for about 10 years now, Play puts some fun back into Java web dev.
Like a couple other commenters, I come from the J2EE world and always found the MVC frameworks overkill for most non-enterprise apps (even some enterprise apps for that matter). I really like all the niceties they have integrated into Play. It's intuitive, easy to use and you can get something up and running fast (very fast). To get my feet wet I've created a URL shortener app. It's a pretty simple app, but has allowed me to explore and familiarize myself with the features of Play! It's been a great experience using Play! thus far; I've just started a more "robust" application using Play! and hope it continues to exceed expectations.