Ember 2 was released middle of last year and the transition was super smooth. Ember's update pipeline is strict and the backward compatibility is serious. Big startups and corporates are switching to Ember, because they want results... Luckily, we can say, at the moment Ember.js is at least 1 year, but more likely 2 years ahead of other js libraries and frameworks. The framework really matured, the best bet nowadays if someone plan to build larger frontend application.