I like how easy backbone is for building out an application from scratch or adding new features when needed! It's also very helpful that they have such great documentation available online as well so you can learn quickly without having any prior experience in javascript development (which i do not).
There are some things about backbones approach which could be improved but this isn't really something one would complain too much about unless working at large scale where performance becomes more important than ease of use/development speed etc. A good starting point if looking into using JS frameworks - especially ones built around MVC design patterns e.g., AngularJS & ReactJs.