I haven't touched it in a year or so, but I really enjoyed using EmberJS over the other frontend frameworks I've used. One reason is that it attempts to be a kitchen sink framework. In the React ecosystem you have to piece together your own framework, which is cool if you have the time to evaluate each piece and glue it on to your project. But Ember comes with pretty much everything you need -- routing, state management, testing, temolating, etc -- straight out of the box. And the update cycle was nice for an organization to follow for reliable maintenance.
Obviously, it comes with constraints. You can't really swap out parts/libraries if you find a better one to suit some need. And you can't really stray too far from the beaten path; you have to do things The Ember Way. But the consistency and organization made for a really nice developer experience.
Also, I found the community really friendly and welcoming, which has not been my experience in the wider JS world.