I guess what makes me lean towards Backbase is their tutorials. This is a very nice one on how to create a small 1 page site. - http://www.backbase.com/#dev/tutorials_examples/tutorial/beginner/introduction.xml[5] I'm reading over the YUI docs and they aren't nearly as easy to follow. Heck, I'm stuck on the yui-grid atm. I would think that with all the money and resources that yahoo has, they could have included a few detailed tutorials.