(2 hrs. to d/l 1.09 GB :-/ Comcast monopoly in my village, etc.)
Safari 5.0.2, though, opened with a hitch-in-the-getalong:
Blue line of running scripts paused, sometimes interminably at various stages, various URLs.

Had opted also, to check out latest version of Snow Leopard Cache Cleaner
http://www.northernsoftworks.com/
Turns out, as you'd suspect -- cache 'cleaning' is a resort you use when all the other thought-experiments have failed and your machine remains randomly soggy and hard to light (aka cigarette in a urinal.)
No need for moi to go there.

But amongst the several clever inclusions were:
ClamAV + update dB access, beaucoup listing of various bits of interest and a slew of other handy things as per website, including:

"Optimize Safari web and icon caches"
(as well as tune a couple values in stack for 'broadband' -- all these reversible if you don't Like the difference.)
Ran above: now see fastest loading since when I had the (Real) 'HS' trial … even with my crippled/filtered feed. Still gets clamped at 184 KBytes/sec, after brief initial spurt, per iStat.

So with a free virus ck, no root-kits (at least in their collection) and an abstruse tweak to the New-Safari's communication skills … it's copacetic on Day 2

(Yeah I suspect you'd have found the glitch producing script delays, via CL + lore ... but for us mere mortals..)