I'm in the research phase for a web application I'm considering building and need some advice on the best choosing the best technology for the job.
The app will make heavy use of dragging and dropping widgets onto a page and on top of other widgets.
Two frameworks I'm aware of that have good support for this kind of thing are Sproutcore and Cappuccino.
Are there any others technologies I should be aware of which would do a better job?
For an example of the type of application I'm interested in building, please see http://gomockingbird.com/ (a cappuccino application).
Though I must emphasise I'm not trying to build a mockingbird clone, this is just an example of the type of drag and drop functionality I want in my app.
I can't speak for Sproutcore but Cappuccino has great, easy to implement drag and drop. See the Cappuccino Scrapbook Tutorial for example. If you follow along the steps you can decide if Cappuccino is overkill for your application. The Floor Plan demo app also demonstrates Cappuccino drag and drop in action together with some extra niceties like rotation controls on widgets. The source code is available. Personally I think writing an app like Mockingbird without a full power framework like Cappuccino would be frustrating.