I tested your demos with Firefox 2.0 running on Mac OSX 10.4, and I found a few bugs:

• Shadows don't work
• In the advanced image gallery app, on the left bar icons do not appear
• Sortables work badly: when sorting them, they float and do not stay ordered (I don't know how to explain it better: it's better if you try it by yourselves)
• When using selectables, if you select an element then there's no way to unselect it.
• Using resizable with textareas and images creates a lot of problems
• Slider with steps don't work

I hope you'll manage to solve these problems soon: I'm very interested in jQuery UI, and I'd like to use it on some projects.