The 10/10 mbit service has a 40 Gig cap, but I myself have crossed it and never heard a complaint from SureWest The 20/20 mbit has NO CAP.
EDIT: I just found out that the link goes to my own post saying there is a cap. They have changed it since then, the 20 mbit doesnt have a cap anymore, and I doubt the 50/50 would.
