Just a counterpoint, but we've had a lot of pain with Ember, especially Ember Data, with only senior developers working on an app - figuring out the right areas

Just a counterpoint, but we've had a lot of pain with Ember, especially Ember Data, with only senior developers working on an app - figuring out the right areas to modify to implement a feature/bug fix was unnecessarily difficult, and some of the recommendations we got from those closely aligned with Ember (including from a former core dev) from a maintainability perspective were highly suspect. We ended up switching to React by rewriting the Ember app in a few weeks and moving significantly faster as a team, gaining more flexibility & better abstractions (which we had to write, but it was not a problem with our engineers' quality). Since then, my whole organization has only written new UIs using React to my knowledge. I personally would rather use Angular (latest) or React than use Ember again. I do appreciate some of the things Ember has brought to the ecosystem though like a robust CLI ala Rails, but I think the routing convention needs more flexibility and Ember Data needs some love to fix the ease of getting into some buggy situations.