I'm a long time rubyist and I believe that I'm far more productive in a dynamic language that has good facilities for interactive development (i.e. a repl).
Clojure gives me this productivity benefit while offering much better performance than ruby, better concurrency features, and does not require crossing a bridge of any form to interact with java libraries. It can also be compiled into java classes so I can make libraries for java people without them needing to know or care that it's clojure and not java code they are running.