UPDATE 2011-02-10: Last friday (Feb 4,) I called to cancel the service. The rep said she would "reset my account and equipment" and extend my 14 day trial period by 7 more days. I decided to give it another try. It's been fine since, but I am just now reaching the 8-9GB usage since the account reset, so the big test will be if things work well over this weekend.
UPDATE 2011-02-19: I wound up cancelling the service a few days ago and sending everything back. After the account reset, the service worked fine for a few days then slowed to a crawl again.