I've used Grails for various projects. From full web oriented architectures, to RESTful APIs, even for console applications. Its Convention over Configuration nature makes it extremely quickly to get started with any project and just modify what you need from the initial sensible defaults. Personally, coming from JEE, where you have to edit thousands of XMLs and properties files, it was awesome. Groovy is a very powerful and comfortable language. If you come from Java, you'll find yourself loving it right away. Before choosing Grails, I considered Ruby on Rails, but didn't like having to learn a completely new and wheel-reinventing language. Grails has everything RoR and many other frameworks has, using a familiar language and industry proven backing technologies.

* convention over configuration * relatively easy to learn * many useful plugins * built on top of mature technologies (Spring, Hibernate) * Groovy-powered

Groovy: It is easy to process web data with groovy since its allow dynamic typing. Strong typing is good for making control structure more realiable Gorm makes it very easy to manipulate and fetch data from database and its intuitive to use Running environments (test,prod,dev, custom) makes it very easy to apply different behaviour for the system when its on test, production or development or in continunous integration. Plugin system and dependency management is very powerful way to control the dependencies of your project. Java-nature: Environment is the same in all the servers no matter if you deploy in windows or linux (different distros) Java-nature: Application is alive even if there is no page load, like in php. Threading makes it easy to manage background tasks without cronjob.