As someone who doesn't build a lot of SPA's, it's a godsend. Keeps the UI structured and decoupled, but doesn't get in the way. I wonder if it really classifies as a "framework"? I feel like it does, since if I'm using it I'm not using a more traditional "framework" like Backbone or Angular; but at the same time, it doesn't come with all the usual restrictions of traditional frameworks (nor does it provide everything they do, but that's kinda the point).