I really don't think that the Acid Test matters a whole lot... It basically boils down to doing things the IE way, or the Mozilla way. As long as Safari works with all of the sites that Mozilla-based browsers work with (which it does, for the most part, except for XUL driven sites), it is in good standing.
All of the tests in the world don't change the fact that we still have to deal with IE, which is quite unfortunate, and similarly, that Mozilla has to work with sites that work best in IE.