As with all Steve jobs keynotes, everything is great, all Apple apps are the best of the world.
The part about Safari 3 was no exception, and he mentioned that Safari is now the speed champion.
As always, speed is subjective and some times difficult to test, but I remembered the ExtJs library speed tests for DOM matching.
The cool part of these tests is that they do about 28 tests with several different JS libraries. Its mostly a test to show off ExtJs DomQuery speed, but it might helps us to test the speed assertion. And best of all, anybody can do it.
So, open up the three browsers (I used Safari 3 beta, Firefox 22.214.171.124, and Opera 9.21, all Universal binaries running on my Macbook pro laptop) and on each one open up the test page. I switched to 10 seconds timeout on all three browsers just in case.
Then start the test, one browser at a time, and compare the results. I used the DomQuery column only, too many numbers.
The result? Safari was the fastest but results where not uniformly faster. Some tests he was 3 or 4 times faster. Most of the times it was only slightly and in one test (and one test only) Opera was the faster browser. On all tests, Safari was faster than Firefox.
So it looks good. But don't take my word for it. Do it yourself.
One last thing: I'm happy with Safari for the vast majority of my browsing needs. Its fast and all the pages I visit on a regular basis work with it. For web development, you can't beat the Firefox+Firebug combination.