I had Comcast for a few years at my old house and bought my own modem. It was a no brainer, $80 for a modem vs $10/month to rent theirs. Well after about 2 years I got a bill saying that I owed them for rental of the modem. I called and fought with them. Even when I cancelled my service they kept asking for their modem back. Luckily, my new house is in an area that has Metronet fiber internet. I've switched and use them for internet and TV and love it. I've had zero issues so far (though it has only been 7 months)