Most frameworks weren't even at 1.0 stable yet. I initially wrote a fairly extensive prototype with Ember, but there were breaking changes so frequently I couldn't keep up with the learning curve. In the end I chose Angular because it had the best documentation, Google dogfooding, and testing was an obvious priority. Worked out so well we're on our 4th major Angular app now.
It's a really tough call. I've been wrong (and right ;-) multiple times going down either path.
The last time I had to make that sort of choice we went the set-based design / real options path and developed both in parallel for as long as we could. More expensive, but lower risk. I'm glad we did coz the decision we made four months in on which one to drop wasn't the one we would have made at the start.