I have to admit that i did not really want to get into another language this year. Its so much effort and usually so little gain of it. But what can you do sometimes you have to ;-).
While evaluating web platform alternatives we began with JSF2/JSTL/JSP/Struts. None of them seemed suitable for our needs. None of them seemed usable either. We began to look around for much more lightweight frameworks and thats when we started looking at Grails and Spring MVC.
As i said before i began reading the book with a lot of scepticism, i thought it would be another messy language like ruby etc.
Half way through the book i changed my mind completely and i must say im really impressed. Its a very rare thing to hear from me so it deserves extra emphasis. Im impressed by Grails and Groovy and im quite impressed by the book as well.
Book is very well written and shows you very many of the things you can do with grails. Its structured well and easy to read. It shows simple and more complex examples. No hello world nonsense. Its a really useful guide!
The only thing that i miss is the feeling of comfort that i know how to write in groovy but i guess no book can provide that : ) Its a different language with different practices and very different concepts. Closures and duck typing is not that strange for jquery/php developers but the concept of 'magic' behind the scenes is a bit overwhelming.
Again, i liked the book a lot and i would recommend it to almost any Java developer. I would also recommend it to PHP and other developers to have a look how code could look like and what could be done.
Book explains in details how controllers / views / models work. You learn how to create services and tag libraries (which by the way are great). You will learn how to create and use plugins, how to develop multi step forms and many more.
Final score 9/10