Does Ember have a persistance layer ? like backbone sync ? anyway ,Ember is far from perfect too. The best javascript framework , though not free , is Ext JS.
https://github.com/emberjs/data
http://emberjs.com/guides/ember-data-lifecycle/
https://speakerdeck.com/tomdale/30 slides for the video below
http://www.youtube.com/watch?v=djhAsWGOImk Tom Dale - Ember-data