I have used Polymer extensively in the past. It is a great library to build web components with, and although I no longer actively use it on a daily basis, I wanted to check on what is coming down the pipe with Polymer 2.0.
Polymer is built on top of the Web Components specs, offering conveniences on top of it. These conveniences include template based rendering from a chunk of HTML, template binding propagation, binding for event handlers, etc.
Google IO 2017 had a great presentation on Polymer titled Future, Faster: Unlock the Power of Web Components with Polymer, which you can view here if you have the time:
Allow me to summarize what I felt were the important insights below: