Advice needed - Best Ajax UI Frameworks?

[eluser]nmweb[/eluser]
The problem with Ext for me was that it was/is just unclear. It's not about commercial vs. not. Before the whole fuzz in the blogosphere I didn't quite get their licensing terms, afterwards I was just lost in all the legal chatter. I believe the issue is solved though although I don't know the how and the why. Anyway, it's just bad publicity for a project when there are issues over its license and it scares away potential users of the project.