Duane O'Brien, engineer on the BrowserLab team has a new blog post on the BrowserLab Team blog that you might find interesting. It covers when/why you might see rendering differences between the BrowserLab browsers and your local browsers. Good info.
http://blogs.adobe.com/browserlab/2011/07/11/why-does-my-page-look-dif ferent-in-browserlab/
Bruce
Bruce Bowman
BrowserLab product manager
BrowserLab Team Blog: http://blogs.adobe.com/browserlab
Twitter: @brucebowman, @adobebrowserlab
North America
Europe, Middle East and Africa
Asia Pacific