Their blog entry covers the details completely, but at a high level, here is what you can expect.
- Fully compatible with jQuery 1.3.
- Updated plugins. (These are the plugins like progress bar, etc, that I've been blogging about with the RC.)
- CSS framework. (Ditto above. If you remember, it took me a little bit to get it working right, but once I understood the system, it was trivial to swap out different themes.)
- Offline documentation. (Hopefully they can make a snazzy AIR app like the core jQuery library has!)
- You can download all the themes at once. (Handy to make it quicker to test out the default themes.)
- A darn nice Getting Started guide.
- And more - again, please read the official blog release. Oh yeah, and they now have a blog: http://blog.jqueryui.com
I'm pretty excited about this. I've said before that sometimes the wealth of plugins can actually be a detriment to a new user. ("Ok, I need a tab control. What - I have to pick from 500 plugins???") So seeing the UI library mature like this really makes me feel more comfortable about jQuery UI as a whole. Congrats to the team.