I have found a few bugs already.
I use
www.logmein.com to remote control Macs and PC from my Mac on a daily basis. (BTW its a great FREE product) Anyhow there is a Mac plugin to speed up the remote control speed from logmein.com, it works great in Safari, hangs FF3 and rails both cores in my macbook to 100%, I have to kill off FF3. This has been a problem since I started messing with FF3 at Beta 2.
Lots of little page render problems on the Mac versions. For instance
www.teamxbox.com has a black toolbar across the top. On Safari, FF3 for Windows and IE even, it covers up the "Contact US" and the end of the toolbar which is correct, but not so with FF3 on the Mac. To many little render problems to mention, none show stoppers but it just makes the product look less polished.
The flip4Mac media player plugin for OSX, works great in Safari but is missing the control buttons (start/stop) at the bottom left of a media player enable web page.
http://xboxmovies.teamxbox.com/xbox-360/7109/Battlefield-Bad-Company-Run-Wild-Trailer/ blame it on the plugin, but its been a problem on all pages that have media player embedded since FF3 B2. Works just fine in Safari.
Sadly this is the worst. I have a .mac account and host a simple photo web page created in iWeb 08 up on my .mac account. The photo page wont display my photo albums under FF3 for OS X or Windows. Works fine in Safari and IE.
http://www.lindloff.us/Little_Lindloffs/Photo_Albums/Photo_Albums.html
That is enough for me to stick with Safari. I really wanted it to be my main browser, its fast and looks good. Hopefully these issues will be fixed with some new plugins and some bug fixes.
Here's to Safari 4.