I didn't jump in head first initially because I was still trying to use jasmine for everything and felt the switch to QUnit would be painful (shows how little I knew about either framework). But after I spent some time unit testing ember.js components with QUnit, I started playing around with the ember-testing package and now I can't say enough good things about it. I think of it like using all the good parts of selenium without any of the slow feedback cycle.
I decided to do a short screencast on the subject to show people how to use it for both unit and integration testing. I also show how to run your QUnit tests with the karma test runner (with some help from the ember-karma-preprocessor plugin to precompile any handlebars templates)