BrowserStack - Live, Web-Based Browser Testing.

Ive been using www.crossbrowsertesting.com for this. Are there any USP's here that make this better out of interest?

They both do similar things, I think that crossbrowsertesting fails when it comes to testing localhost though. I don't think you can just run a rails app by pointing to where the files are, since rails runs on its own test server activated through the terminal. If you are only testing basic html/css then it will work fine

Having to fix an IE7 bug, this saved me the other day - super awesome and great tool for developers!

Same here, this is my default for cross browser testing. Setting up virtual machines was somewhat of a headache, and the speed at which I can test different browsers is awesome. They also allow localhost to tunnel into the site so you can test your builds extremely quickly. Highly recommend!