Given that Chrome and Safari use webkit has anyone yet found anything that renders differently on Chrome than Safari? Is there any reason at the moment to test sites on both, o
Chrome and Safari have different font rendering on Windows. Safari includes Apple's font rendering which to a Windows user is a bit fuzzy-looking. On OS X, they both use the platform's native font rendering. So Safari looks like OS X on both systems, whereas Chrome looks like the platform it's running on.
This is in addition to other points mentioned by people who know more than I do. :)