ethernet :
its easy to install (literally plug in the cable and set your connection to connect) and you're able to run about 100 meters of the stuff, so your modem can literally be in the roof if you like, without any type of signal loss (talking about the transmission of data, not radio signal)
you will have endless trouble with USB, plus, anything more than 5 meters would give you trouble. You need to install special drivers.
USB is 1mb (but not true 1mb) and the ethernet cable runs at 10mb (so you know the cable is not the bottleneck)
I've also heard of folks getting better ping times with ethernet than usb, shaving off something like 40ms.
If you're capped, it could be the reason why you're getting such slow speeds, if your signal is k@k, it would explain why you get such low speeds, and depending on the tower and how far you're from it (even if you have all 5 lights on) is also a factor.
I've noticed that when you connect with the UTD through the ethernet cable, doesn't matter how sh1tty your signal showed on the UTD, it shoots up to 5 green lights immediatly (sometimes it will alternate, depending on your actual signal strenght)
If you have 5 lights without connecting the UTD at all (you're using the desktop monitor thing, so you could probably get a good idea of how strong your signal is) it will allow you to asses what is wrong.
As slimothy used to say, try and find your sweet spot, move the modem around and check for different results.
good luck, btw, get your adsl application ready, if they drop line rental (thanks rpm!) i'm definately getting adsl
