[erikpukinskis]

My experience pretty much parallels yours. These frameworks are at the cutting edge. Only a handful of big apps have been made with Ember or Angular, and so the core teams are constantly bumping up against weaknesses in their designs which can only be addressed by making changes that break apps.

From reading the Ember discussion lists I get the strong sense that the core team is willing to make difficult breaks, but that they really try to only do it when it's absolutely necessary for the long-term robustness of the platform. A lot of thought seems to go into which problems are getting solved now, which are put off til later, and which interfaces get torn out and rewritten.

I just spent several weeks upgrading my app from the earlier Ember RCs to Ember 1.0 and the latest Ember-data, and while quite painful, I feel good about it because I don't think the core team made those changes lightly. My sense is they are looking out for us.

[Bahamut]

I'm currently working on a big Angular app that is about to move into production (although it's not to be something that's widely used in public) - we have found that Angular causes everything to be structured in a nicely organized fashion overall. This app is not structured perfectly by any means either, due to bad design on some of our pre-existing code base.

From what I understand, big Ember projects have turned out well for Ember devs - I can confidently say that I feel the same way about big Angular apps. I have built several big ones, including an online assessment platform (frontend by myself) and an online assessment platform/management system (with a team of ~10, 3 of us on frontend).

From my experience, the Angular team has thought things out on a high level, which I greatly appreciate. They are big consumers of their own product, as Angular is used quite a bit with Google's own sites - here is an example of an Angular app, with Angular being used to implement parallax scrolling (and probably more): http://www.google.com/nexus/7/