I tried using it a couple years ago, just as a sample. It's very very unlike any other language I've ever used. Its weirdness comes from a more practical place than other weird languages, which typically have more of a mathematical or academic axe to grind (APL, *ML, Haskell). Lisp-y, and smalltalk-y with a lot of its own dialect. Lots of batteries included. Now that it's open source I'm more interested in putting the time into understanding it better.