Of course, having done my bit of Rails dev I don't actually believe that Grails or Rails are more productive than each other if you're using purely Groovy (in the case of Grails) or purely Ruby (in the case of Rails). In fact Rails might still have the edge here due to its greater maturity, nevertheless if you're mixing Java into the picture their is really only one winner. This is what the ALTERthought guys have discovered on their Fortune 200 Grails project.
It is of course a growing trend. More and more and more consultancies are discovering that Grails is easier to integrate with existing Java and legacy systems. With Grails you can do things like:
- Use an existing Hibernate domain model written in Java and still get the benefit of dynamic finders, persistence methods etc.
- Re-use existing Spring services as Grails built entirely on Spring with all its enterprise application integration goodness
- Leverage an array of enterprise proven technologies such as Sitemesh, Quartz, Lucene, Compass ... (this list could go on)
- And in the upcoming 0.6 release, thanks to contributions from JetBrains, you can jointly compile Java & Groovy and have circular references between the Groovy and Java code (a Groovy class is just a Java class after all)
The other revelation that Java people are discovering is that they no longer need to abandon their existing Java knowledge to get RAD development. The Java platform now has its answer to Rails, why go else where?