I have been using it on a project for 9 months now it has been great to use. I haven't used Jython but I it's the only scripting language I've seen besides Rexx that defaults to using BigDecimal for numbers. Contrary to what many people write, it's not dead. My experience is that bugs get fixed relatively quickly. The project is definately moving closer to a 1.0 release. Most of the bugs that I've seen have been corner cases that don't affect 99% of what we do. Just my experience.