ReactJS is a solid solution if you need to ship something _today_, but I think the trend will continue towards WebComponents as they become standardized across vendors (if not Polymer then x-tags, if not x-tags then... etc). In that sense, it's better to familiarize oneself with the technologies that we'll be seeing more of in the future just as we did with new HTML5 elements a few years ago.

@jastanton phrased it nicely in another comment here: https://news.ycombinator.com/item?id=7971847