AngularJS is great ( my first app every with Angular : http://paraiso-flickr-search.herokuapp.com AngularJS forces developpers into separation of concerns , DI , which are good things , but until one understands why they are good , one will not like AngularJS.

Backbone is in my opinion more a library ( like jQuery ) than a framework. it doesnt force people doing anything , it provides helpers and conveniant "classes" to work with.

But it doesnt solve most of the problems regarding app architecture. AngularJS solves app architecturing problems in a elegant declarative way ( like Flex before it ).