Windows Safari != OS X Safari (AJAX issues)
For those of you expecting a level of comfort that the Windows version of Safari works just like the Mac version, think again. We just encountered a pretty serious problem that happens only in the Mac version surrounding the ASP.NET AJAX framework. I haven't been able to nail it down yet, but stuff coming back to the UpdatePanel on the client is either not there or garbage (haven't figured out which). I'm not sure if it's because we have dynamically created UpdatePanels and validators or what, but it's ugly.
Make sure you test your stuff on an actual Mac. If your stats are like mine, 5% of the market is too much to ignore.