Difference between Angular Dart and Polymer Dart
In addition to the discussion referenced by @Paul Collingwood which contains a good explanation.This similar question has an extensive explanation: What is the difference between Polymer elements and AngularJS directives?
There is a recent demo that shows how to combine Polymer's elements with Angular for routing and other app logic.
It looks fun, but I am not sure whether as of today the generated js code size is reasonable enough.
https://github.com/sethladd/dart-angular-polymer-data-binding
Slides for an accompanying talk: https://docs.google.com/file/d/0B3tMhVSd9MFIV0xfRm5NZ0VpNzg/edit
Blog with a summary: http://blog.sethladd.com/2014/02/angular-and-polymer-data-binding.html
Slide 66: