Visual Paradigm for UML: why have I not heard about this product until now?

For ages I've been looking for a capable UML-based design tool that isn't Rational Rose, particularly one that runs well on MacOS X. I stumbled upon VP UML this weekend, and I'm really impressed.

Written in Java, VP UML runs well on OS X (I haven't yet run it on Windows). It handles all the static and dynamic diagrams you would want, and has nice documentation / model annotation features. I'm still trying to figure out how to organize classes into packages, as I really like to have namespaces in models. It seems to support this, but I haven't quite got it.

It has exhibited some minor funkiness, but no deal breakers.

This could potentially replace Rose. Very interesting.