I've been using Ember for the past few years, and while I like it, I almost always use React when dealing with realtime components; Ember just doesn't handle frequent component updates very well. I have even resorted to embedding React components inside Ember components to get performance gains.
For example, performance went from ~4 FPS per re-render of a realtime Ember component (absolutely terrible) to 60+ FPS by writing the exact same component in React and embedding it into the Ember component. I'm not sure where the bottleneck was, as debugging Ember performance is quite a headache.
You also have to buy into a lot of conventions, especially if you're using Ember Data, and those are not always easy to buy into.
If I was starting a new front-end project that was non-trivial, I would likely use React even though I do like Ember quite a lot.
For example, performance went from ~4 FPS per re-render of a realtime Ember component (absolutely terrible) to 60+ FPS by writing the exact same component in React and embedding it into the Ember component. I'm not sure where the bottleneck was, as debugging Ember performance is quite a headache.
You also have to buy into a lot of conventions, especially if you're using Ember Data, and those are not always easy to buy into.
If I was starting a new front-end project that was non-trivial, I would likely use React even though I do like Ember quite a lot.