Depending on your requirements don't rule out other frameworks.
I use Knockout (which is supported, just had a release, picked up some new core devs and added component support) extensively and I like it a great deal.
It's not as large as either Angular or Ember but it's worth a look.
Steve Sanderson has an awesome video on it [1] which is worth a watch even if you aren't interested in Knockout, fella clearly loves and is passionate about what he does.
I use Knockout (which is supported, just had a release, picked up some new core devs and added component support) extensively and I like it a great deal.
It's not as large as either Angular or Ember but it's worth a look.
Steve Sanderson has an awesome video on it [1] which is worth a watch even if you aren't interested in Knockout, fella clearly loves and is passionate about what he does.
[1] http://blog.stevensanderson.com/2014/06/11/architecting-larg...