You can check here with this tutorial, how easy to write a complex application with Ember.js: http://yoember.com
Here's the doc for ember's: http://emberjs.com/api/classes/Ember.Component.html
Versus react's: https://facebook.github.io/react/docs/multiple-components.ht...
Versus angular's: https://docs.angularjs.org/guide/component
If you compare them, you can see that react and angular focus heavily on component oriented architecture, while with ember, not so much.
Edit: wrong link.