Am I the only one who can't stand their interfaces? It looks terribly out of place on OS X (the icons, those tabs!). I don't know why it seems every app built on Java has to look like that.
The Cocoa bindings for Java are deprecated; so "every app built on Java" _has_ to look like that.
I'd rather have a good and usable tool than a pretty one; instead of wasting time fighting unsupported bindings or trying to replicate them (likely poorly).