Ember.js defines itself as a framework for creating ambitious web applications.
Moreover, the team behind the framework commited to stability without stagnation. This means maintenance will be eased as much as possible (no big application rewrite at each update), without having to sacrifice new features.
I have been developing with Ember.js since the first versions and have used it in many projects, from internal prototypes to offline web applications.
Recently, I've worked with deliver.ee and helped them kick-start their project. Then, I helped Scalingo transition their aging Ember.js application to actual standards: ember-cli, latest ember versions, best practices, while making sure future updates will be seamless.