Besides, it's hard to predict if either will be still widely used for new projects say 5 years from now. So, becoming a one-trick (or rather one-framework) pony probably isn't the wisest path in the long run. Rather try to take in general best practices, design patterns and approaches and become someone that can work comfortably with both React and Vue.js or in fact any other new JavaScript framework that might come along.
That's a misconception a lot of outsiders make about the JavaScript community. There's not even close to one winner. It's not "WWW World Champion React vs upcoming Challenger: VueJS". There's probably about 10-20 (possibly even more!) production ready frameworks you could be using that have strong community backing and ecosystems. VueJS and React are merely approaching the pinnacle of what a full stack isomorphic framework can be. The others will follow.
Facebook is not doing this for complete charity. At the moment their interest is aligned with react being open source but you never know when that will change. And when that happens, the artificial illusion of support will go away.
I'm not just pulling this out of nowhere, I actually use both react and vue, and think react ecosystem is too convoluted. It's a matter of opinion but I don't think it's just me who feels that way.
For example, watch this 5 min React Conf talk on how Flipkart has made React a big part of their tech stack.
Vuejs might do well for webapps due to its simplicity alone.
[1] http://weex.apache.org [2] https://github.com/alibaba/weex/releases/tag/v0.10.0
Ultimately, I think the winning framework will be one that compiles. Something like svelte[1]. It's how most other software is made for good reasons.
Popularity and some-big-company's supports is most important thing for them.
Angular 1 was a framework, Angular 2 was a piece of a religious writing that people developed to pad their resumes.
