The UI elements are good. I checked the demos. (the charts which I wanted to see isn't complete yet). But The question is that, is this style-able? I ask this coz one of the UI frameworks I used, Sproutcore, isn't stylable.
Yep, XUL components are indeed stylable (So will be charts).
For example:
xul|menuitem[type=radio]::image {
background-image: url(media/menuitem_radio.gif);
}
or
xul|listcell {
padding: 5px;
}
I like that you can make custom tags. Especially the Google Maps tags really seem to make Google Maps easier to use.