What you’re seeing is probably a combination of things. The Round Trip Time from the test equipment to Famous Dave’s web servers looks to be ~15ms and to UDR it looks to be closer to 80-90ms.
The way the pages are structured, UDR may “feel” faster than Dave’s if the latency was changed because it looks like the Dave’s site doesn’t render anything on the screen until the massive swf downloads. UDR on the other hand downloads their massive swf in parallel with a lot of the rest of the page loading. Being closer to UDR will also eliminate the enormous penalty they are seeing by not using persistent connections (all of the round trips for connection set-ups really hurts).
The fact that either site loaded reasonably quickly is also a function of the fact that testing is done on a 15Mbps FIOS line. I haven’t had time to do it yet but a version of the site that we use internally at AOL actually has a DUMMYNET traffic shaping device in front of it so you can see how a site would load at 1.5Mbps DSL and 56Kbpsp dial. I plan on making those available when I get the time to set up the configs.
Either way, both of those sites have plenty of room for improvement in performance as you can see from the optimization results