I read this article about Meteor recently. https://www.discovermeteor.com/blog/the-state-of-meteor-part... Looks, they have to find a new way. It is kind of the same story as happened with Angular, the Angular 1 was a cul-de-sac and they had to build up a totally new framework from scratch.
Meanwhile Ember adapts the best solutions all the time. Ember begun to use ES6 almost two years ago. Implemented React inspired view layer a year ago. Server side rendering just released a couple of weeks ago. Ember-cli stable version is released a year ago, which is so good, that Angular 2 would like a similar cli tool, and of course Ember-cli team helps them. Hopefully Angular 2 will have a cli tool by middle of this year.
We could say, that Ember.js is at least 1 or maybe 2 years ahead of other javascript libraries or frameworks in more aspects at the moment.
Suggested pages: http://www.emberjs.com, http://www.ember-cli.com, http://yoember.com, https://guides.emberjs.com/v2.3.0/ http://www.emberjs.com/community
Here is a fresh report, which mirrors how serious the community behind this open source project: http://emberjs.com/blog/2016/01/23/core-team-face-to-face-ja...
Be careful, because if you start learning Ember.js, you will fall in love and you don't want to work with other javascript library any more. ;)