I like the rendering speed of Safari 4It makes my 1Ghz PowerBook running Leopard, Blaze !
I do however miss the blue thermometer.
Enter your terminal (It's in the Utilities folder in your Applications folder) and copy and paste the following two UNIX commands after the $ prompt:
defaults write com.apple.Safari DebugSafari4IncludeToolbarRedesign -bool NOhit return after each one... and you will revert to the standard URL address field with the blue thermometer.defaults write com.apple.Safari DebugSafari4LoadProgressStyle -bool NO
If you don't like the tabs being on the top of the tool bar instead of below the Bookmark Bar, then also copy and paste this command at the $ prompt in terminal:
defaults write com.apple.Safari DebugSafari4TabBarIsOnTop -bool NOand press return.