Safari on windows is terrible. In my own tests last year it kept erroring out or rendering incorrectly. http://www.craftymind.com/guimark2/

Safari 5 on OSX Lion is terrible.

I'm usually a safari fan, but since upgrading last week nothing but trouble. Opened Chrome and Firefox a few times instead but I'm to accustomed to Safari now... and admittedly the gestures are AWESOME.

I was hoping the 10.7.1 update would have fixed it but nope :/ Maybe 10.7.2, I feel my days numbered ATM though

Earlier versions of Safari on Windows seem to work fine

It turned out to be a bug in their testing framework.

Is this what you're referring to?

http://code.google.com/p/selenium/issues/detail?id=1329