So, I’ve a got a little crush on the BrowserStack web app for Cross-Browser-Cross-OS Testing

BrowserStack | Live, Web-Based Browser Testing

Awesome.

You can check it out with the Free Trial and pricing starts at $19/month for a single user. Do it.

Pros:
Live testing for interactivity (but also a screenshot option to view a snap shot of multiple browser/OS configurations)
No need to switch between virtual machines