I'm curious: what about the Backbone version feels "cleaner" to you?
as for the cleaner part, I didn't like the fact that I need to call _super().
On the other hand I really like .property and .observe in Ember.js :)
Demo: http://jsfiddle.net/bruth/bufeK/
Source: https://github.com/bruth/synapse/blob/master/src/synapse.cof...
Synapse is an elegant API for data binding. Subjects and observers clarify many issues for data-flow interfaces.
The boilerplate in Backbone shrinks significantly when expressed with CoffeeScript. Synapse's source is expressive, well-documented and only ~200 lines.
There's a nice pattern here for checking ids for presence before adding new models, but nothing inherently Ember or Backbone about it.