This looks interesting - we've been pretty happy with crossbrowsertesting.com until now, which is also worth a look.

Here's what I'd love next - we'd write a bunch of QUnit javascript tests, put them behind a private url on our staging server, and then be able to run those tests from the command-line on multiple browsers (through BrowserStack, say), and spit back the output in a form that Jenkins understands. I'd certainly pay $20/month for that, and maybe more if it was great.