I did try it and even though it's advertised as somewhat backward compatible it did break lots of things, which was totally expected and it's a major release.
Also we couldn't figure out a lot of things, like how can I access the $children like before, why does everything show Object proxy in console, etc. Posting on SO and forums also didn't yeild much help since everyone is still discovering it too I guess.
So in the end we decided why fix something which ain't broken for now. Vue 2 still kicks ass performance wise and is really easy to use.