Are there any demos or sample apps to play with? The last time I tried SproutCore 1.x I was not satisfied with the responsivnes of the UI, even on Chrome there was a noticable delay when switching between tabs or moving sliders.

The focus of SproutCore 2.0 is building views using Handlebars and the ability to use these views and the data layer in ways that play nicely other frameworks and web technologies. The only real demo so far is the todos app: https://github.com/sproutcore/todos

At the Chicago SproutCore Meetup, Tom Dale mentioned that they are working on a new UI toolkit to take the place of the one in SproutCore 1.x. There has been no word when that will be released, but I would expect a widget demo of some kind when it is.

Oooh, fancy. I wonder why I haven't heard anything about a new UI kit for SC2 until now. Hopefully it will come with a new look, I haven't been digging Ace very much.