I've had the same ISP (meer.net) for like 13 years, because it was started by some former coworkers. This used to mean there was a high level of cluefulness and reliability, but lately, not so much. About every three months I get some new variant of what happened again today: "Hey, how about we re-number our mail server without telling you so that your firewall is now wrong!" "Oh, and once you figure out what we did, how about the new server says 'relaying denied' at you, how would that be?"
I had to route around them by drafting a machine I have at a different ISP into service as a mail relay. WTF.
I think they're trying to drive me into the arms of Comcast.