I use Polymer at work quite a bit, and its really nice, but it's a completely different approach based on trusting that the DOM is sane and running as close to

I use Polymer at work quite a bit, and its really nice, but it's a completely different approach based on trusting that the DOM is sane and running as close to web standards as possible. React and its 1 billion clones run off of the assumption that the DOM API is not to be trusted, and that lets you target more browsers, even non browsers. I mean have you ever tried to get Polymer stuff to work in Firefox? It's not Pretty.