To start off with quite an interesting website! Now, I visited the main one and the fast DHTML one.
When I first visited your main .com one I didn't spot the scroll bars and found the site of very little content. I'd reccomend that you make the scroll bars stand out more.
With the fast DHTML one I found it was much easier to navigate and faster (suprise! ). The only thing I was confused by was the side on scroll bars... quite difficult to get used to!
Beaides all that, great site!