First of all, I wouldn't call Backbone a framework. It's more like a library. It's only about 1500 lines of code with lot's of comments.
If you use Backbone, you'll have to reimplement/include other libraries to use the right design-patterns. And this takes time.
AngularJS and Ember.js makes these decisions for you which saves alot of time.
If you use Backbone, you'll have to reimplement/include other libraries to use the right design-patterns. And this takes time. AngularJS and Ember.js makes these decisions for you which saves alot of time.