The web components polyfills have support down to IE 10: https://github.com/webcomponents/webcomponentsjs

Start with this: https://github.com/webcomponents/webcomponentsjs/issues/212

Which is why I stopped messing around with polymer. Basically adding the webcomponents polyfill to your DOM tree (because it touches so many things) breaks contenteditable in some weird ways. Which can be limiting to people who use rich text editors (many still decorate contenteditable divs) although iframe-wrapping the editor fixes the contenteditable breakage (at the expense of introducing other problems with extending your editor - try adding custom (say) atmention autocompletes to something in its own execution context).

Also, webcomponents have had some pretty major syntax changes over time, especially when it comes to shadow-piercing styling vs other styling selectors.

Ultimately, I'm looking forward to webcomponents. I can't wait to have proper namespaces and all that. In the short run, though, I've tried the webcomponents polyfill (I wrote a lot of polymer 0.X code for a webapp that I eventually ported to angular 1.x instead when the polymer 1.x syntax meant I'd have to rewrite a lot anyway), and it's not Enough.

Yeah but there's a separate "lite" version for a reason, Shadow DOM support requires wrapping nearly every DOM API. Web Components without Shadow DOM aren't that interesting.