Does anyone have a 100Mbit+ BW test file on a server hosted at ColoUnlimited? I'd like to be able to test the speed at various points throughout the day from a few locations in the US. I'm looking at dropping a few hosts there, but before I pay for shipping I want to see what sort of speeds I should be expecting...

On a more general note, could someone with experience in the field explain the REAL difference between carriers that offer BW for dollars per mbit, and those that offer it for $50 or $90 per mbit? Is the network REALLY that much better? Does it have to do with overseas transits? Antiquated pricing?