MARKUS WINTER Basically they do very similar things but S4M is available in English and German, changes 9 settings compared to Buddy's 7, clears recent searches, sticks to user interface guide lines (uses check boxes instead of radio buttons), warns on start up if Safari is running, etc etc
Safari 4 Buddy is good - but Safari 4 Modifier is better ;-)
P.S. Why are you posting this on all download sites? If you want to advertise for Safari 4 Buddy then this is a rather underhanded way of doing so.
(Version 0.2.2)