All these Rails clones! They think they can just ape Rails' idioms and then they'll have the power of Ruby's metaprogramming at their disposal and -- oh, wait.
rails is a pretty mature framework these days, and it's got tons of plugins that are actually easy to use. It's a pretty steep road to get something up to those standards. When I need something that has everything already neatly solved and ready for cranking out stuff fast -- I always chose rails. I'm currently trying to learn clojure and enjoying it immensely. It's a lot like ruby (powerful and fun) but with easier…
Wouldn't it be better still to use something that is, and uses, Clojure?
One thing (among many) that I like about using JRuby is that I can use Ruby for config files and admin tasks. It may be a JVM language but I shouldn't have to use Java tools for routine tasks.