Pros
-Uses primitive javascript types instead of function wrappers (“dirty checking”)
-Loaded with functionality
-Easy to get started
-Fast development and smaller amounts of boiler-plate code compared to backbone
-Makes testing easy and offers many testing tools
-Working with standards bodies to make browsers operate in the same way as angular
Backbone
Pros
-Relatively mature, proven framework with a strong community behind it
-Many extensions and scaffolding tools available
-Flexible, works fine for a new project or improving an existing one
Knockout
Pros
-Highly compatible with other 3rd party js libraries
-Easy to learn and use
-Dependencies are handled through a dependency graph which targets specific data as opposed to updating entire models when data changes like in Angular.js. This may increase performance in data-heavy applications compared to “dirt checking” which Angular uses.
For more: Javascript MVC/MVVM Frameworks, AngularJS vs Backbone vs Knockout