This is a coincidence, just yesterday i checked out Cordova, Ionic (on todo list, but the demo's on the APK's seem to slow :s), Supersonic seems quite interesting also (and a lot easier then Polymer)!

But what really interested me are the demos from Google (Namely Paper Elements as UI) with Polymer (it's like AngularJS, but it isn't): https://www.polymer-project.org/docs/elements/material.html

Fyi, an index of webcomponents for polymer is available on : http://customelements.io/

There's a designer tool for it: https://www.polymer-project.org/tools/designer/ , here's how to use it http://goo.gl/r8ovXN (it's a responsive maps application, with search input and speech input)