[toddanglin]

That's a fair point. jQuery, jQueryUI, and jQuery Mobile are all very much under the same roof.

The plug-ins are a different story. Some are more "official-ish" than others. So a developer using only jQueryUI must research, find, and add these to a project to "build out" a complete starting point.

We're trying to save developers that time, and provide an unified library that's simpler to learn, maintain, and upgrade. I think it's more than semantics, and when you compare performance, you should also see it's more than just features.

Hope that helps.