Ember.js has released their RC (release candidate) version 1.0.
This is very close to becoming the full release and will give developers a chance to really see what the engine can do. Largely being java and DOM based, it's set to compete head to head with native application programming for mobile by providing key concepts out of the box that native programmers are used to such as controllers, views, models, and routers.
There are already some bis players using Ember.js, such as Groupon, LivingSocial, Square, and Yapp.