I don't know about that Safari ranking. I get a super-fun rainbow wheel at least 2 or 3 times a day on Safari with only 3 or 4 tabs, and I rarely get that through chrome with upwards of 30. Before you give a score to every browser, why don't you back it up with something objective?
These days Safari actually shows that rainbow spinner when the background process that runs the tab is hanging, even though Safari.app itself is perfectly responsive. This usually is indicative of a problem with a site loaded in one of the tabs in the window (I believe Safari does process separation per-window), as opposed to a problem with Safari or WebKit itself.