That depends on yours and the businesses tolerance to outages. If its an every once in awhile thing with quick resolution, that may be acceptable. If it's a once or twice a week thing and you are on the phone with Comcast all the time and its affecting your business, get rid of it. If the Comcast business and T1 cost are close however (if you are getting a great deal on the T1 I mean), then go with the T1.