I have used USB for the past 3 years to get internet from the SACM to my PC/Network. I just changed to ethernet today and I can honestly say why didn't I use ethernet in the first place?
It really does make a difference.
On a lighter note got a 10/100mb Realtek Network Card for £6 and that had a ethernet cable thrown in. So getting a card and a cable wont and/or shouldn't cost you more than a tenner!