I have a lot more experience with Ruby on Rails than I do with anything in the Java world, so I'm coming in from a different perspective. Overall, Grails is much more rough-around-the-edges than Rails is, partially due to its immaturity, and partially because it relies on two insanely complex frameworks under-the-covers (Spring and Hibernate). Rails also has a much bigger community.
But, Groovy as a language has made huge strides, and is a pleasure to work with. Thanks to the improvements made in Groovy 1.6, Grails is quite a bit snappier than JRuby on Rails, and you get amazingly good XML support via GPath. There's a lot of nice features you get by being on the JVM (like concurrency and tons of threadsafe code), but without having to muck about with Java (a language I don't much care for), so I'm having a really hard time of convincing myself to use anything on MRI.
Python is looking tempting, though, I must admit.
As for your Eclipse problems, I can't help. I use Vim and Emacs, mostly because I can't stand using IDEs. For dynamic languages like Groovy, Ruby, and Python, though, I don't think IDEs really introduce any real benefit, as there isn't really any place for code generation, or a need to compile. Maybe try working sans IDE for awhile and see if things are smoother?
So, yeah, I think Grails is worth it. They've done a helluva job in getting things working as quickly as they have, and the Grails and Groovy teams are both really, really dedicated.
