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 is currently using a slightly older version of Webkit than Safari.
Over time it will be updated, of course, but there is the possibility that it will always be a little behind, depending on how Apple release their source.
In addition the Javascript engines are different, which may affect behaviour, although they're both extremely fast.