I'm sure speed will depend on the quality of the GPRS signal as well, so I don't know if there's much value in having your BES provider piping data two you faster than you'd see from your wireless provider in everyday situations.
For grins, I performed the test on my AT&T 7290 without any BES. Located in Manhattan with 3 bars of signal and that site pegs me at 193.6 kbps
Hmm, interesting results. Perhaps AT&T has Channel-on-Demand++
Also - MyBlueBerry *IS* listed in the FAQ. They're also known as MyBlackBerry.us