Safari takes almost 15 seconds to render/complete the page, Firefox does it within 2 seconds (same hardware) Also reproducible with Safari 3.0.4 (523.12)
<rdar://problem/5604784>
Tested on my machine with Safari 3 and Firefox 2. Safari 3 loaded the page significantly faster. The server seemed unresponsive during the Firefox load though, so I suspect this is a server issue and has nothing to do with the Web browsers.
This is very noticeable with a DEBUG build of ToT WebKit with Safari 3.0.4 (523.12) on Mac OS X 10.4.11 on both a PB G4 1.5GHz and a Power Mac Quad G5 2.5 GHz. It's much less noticeable with a WebKit nightly build of r27865, but you can still see the page pause when drawing the horizontal menu (below the page header) and when drawing the vertical menu on the left. (There is also a third pause before the page finally loads.)
I can confirm that this page loads significantly slower in a nightly than in Firefox for me - on a G4, the difference is very large. However, spoofing as Firefox makes the problem go away, so it seems that the site gives us a worse version of itself. I haven't tried to confirm that guess by comparing sources though.
Not reproducible on latest version.