Yes i used it with Cordova for IOS and Android.
Work great for me. Was very easy too.
I saw a few gulp scripts to integrate the two, but i went the easy route and just wrote a bash script, that calls the npm modules that do 99% of the work for you.
The polymer dialog does not work so well for small screens i found, but i have a complicated layout.
I ended up writing my own dialog css. I think the Polymer team are working on this aspect though. So just a matter of waiting for new release.
Also i worked out a way to dramatically reduce the amount of polymer code / and dependencies, even after the vulcanisation.
I call it dist slim. i basically copy the dist folder and remove lots of not needed stuff. It removed about 90% of the files.
These files are not loaded into the browser anyway, but i needed to reduce the size of the app.
Also making all the icons for all the potential mobile screen sizes was a bit of a pain. I think i had about 25 needed.
I will write a script in golang to automate that for the next project.