Judging by the features of the framework I could have chosen Sammy.js. It has a nice API and useful functions that Backbone.js is lacking. The multiple template type support for Sammy is also a plus.
A very important thing is to keep an intuitive app structure on front-end (which I didn’t do in the beginning). Keep all the models, collections, routers and views in separate files and folders. The most suitable structure for our team was this one: