I agree with what they say on that link Dom.
Ethernet alows a transfer rate of up to 100mbps wheras USB1 tops out at 10mbps although both are obviously more than capable of transferring anything you get over the internet up to a 10 megabit line ( I wonder when that will become as common as 512k for home use is now
).
USB2 is supposed to be as fast as ethernet but even then I would still go with ethernet.
Obviously the deciding factor would probably be whether your pc has either onboard ethernet or an ethernet card fitted, as I am not sure it would be worth buying and fitting a card if it was just to enable you to use the ethernet connectivity of your modem :doggie: