About to start a new heavy client-side interaction project, and I want to start it with the right structure so I can move fast and easily maintain it.<p>I've been looking at the following libraries :<p>Spine.js : http://spinejs.com<p>Backbone.js : http://documentcloud.github.com/backbone<p>Knockout.js : http://knockoutjs.com<p>Batman.js : http://batmanjs.org<p>So far, I'm leaning towards Batman, though I've used Backbone in the past and enjoyed it.<p>Has anyone worked with these? What are your thoughts? Why do you like one over the other?<p>Thanks!