Safari 4 which was in Beta stage since 2 months and was already in talks being claimed as the fastest browser claims that right as it passed the Acid test 100/100. And its now out of the Beta stage and launched today for all platforms.

In Safari 4, ESPN and Google Maps render immediately.
Top sites section is seen to display the most viewed websites in the browser.
Alerts the user when a website is updated, by showing a star on preview.
There is a spotlight search option for browsing history in Safari 4. No need to search for the URLs, just a text search would do.

Safari 4 has 7.8X faster at JavaScript than IE8, which is better than Chrome(which was said to have 5X faster than IE8).
Safari 4 comes within Snow Leopard OS too.
It has many added features, and crash resistance, and faster Quicktime.
The new Safari 4 is said to be better than other browsers and any other previous version of Safari and is available for all Operating systems.

Still, until Safari shows some good add-on support like Firefox, many aren’t changing their browser just for the speed. It might have some plugins but the flexibility as seen in firefox is nowhere.