Has anyone here heard of Ember, the JS framework? If so, would you say it's better than React and why?

These two Frameworks have different goals. Ember has a clear concept how you should write your application and gives you powerful tools to your hand. For example theire powerful router and ember-data. This means that every codebase of an ember-application looks more or less the same.
React in the other hand solves only updating the dom and splitting your application in components,nothing more.

The question is, what do you need? Both frameworks have there pros and cons.