Pretty much goes with the territory. Javascript is sort of a mess right now. Everyone is figuring out the best way to do things. The exact same thing happene

Pretty much goes with the territory. Javascript is sort of a mess right now. Everyone is figuring out the best way to do things. The exact same thing happened in previous projects of Yehuda's like the Rails merge where 3.0 brought a tremendous amount of pain, but 4.0 significantly less so. Or Bundler, where people cursed it up and down for the first two years, but once it stabilized it was amazing and now everyone just quietly uses it without problems. I really trust Yehuda and Tom's approach with Ember. Yeah there will be pain and breakage, but that's better than making a long-term commitment to the wrong thing. Over time it will converge (and I think it is already to a significant degree) on the right abstractions and then stability will come, but to do so prematurely leads to an inferior framework. If you need stability in your front-end then Ember (or god help you Angular) is probably not the wisest choice—I would even consider your options of just going server-rendered for current projects to give a bit more time for the ecosystem to mature.