In my opinion, a framework should not be learned so you learned something new - for that purpose it is better to take a look at the concepts for a framework and how it works under the hood. If you don't use it, most of the stuff you learned will be for naught. It's better to use a project you work on, research possible frameworks which might fit and then decide on one of them. You will have real-life experience how well the framewok fits your expectations and how to work with it. In future projects, you might more easily be able to decide on a framework based on your experience with real projects.
If you need some advice for what to learn in the coming months no matter what, I would rather suggest taking a look at Polymer, as web components are a standard and you will have to learn it sooner or later anyway. You can even combine Polymer with React and other frameworks. You could start bundling widgets into external (web) components. That way you can gradually introduce web components to existing or new projects, if you really want to use them.