Grails vs. Ruby on Rails

Are you at the point when you need to decide what will be your next Rapid Application Development framework for your new website? You heard a lot about Ruby on Rails, right? It's soooo cool and sexy and stuff!

But wait, look at that Grails, Ruby on Rails:

Hugely popular in the past ROR (Ruby on Rails) is giving in to Grails. I think the reasons are the following:

1. Performance, performance, performance. Twitter is dumping ROR because of performance. Grails, on the other hand, is compiled into Java and runs in a JVM.
2. More and more Java developers discover Grails.
3. I can't think of anything else right now :)
4.