Just thought I'd throw out SmartClient here:
It's an example of what you get when you follow the "framework does everything but the kitchen sink" philosophy to the end and pile on feature after feature. (It's open source, too!) It's great if you need to hack together a "enterprisey" client and don't really care about style or extendability (rare but these requirements happen.)
The databinding support, controls, and the amount of stuff it does out of the box is absolutely incredible for a free open source framework. But, it's ugly as hell, bloated, and if you want to do anything off the beaten path, you're fucked. But it's a remarkable piece of engineering that goes under the radar (similar to OpenLaszlo) but also a cautionary tale for the Ember guys to not take it too far.