We have Time Warner Road Runner here in Memphis. Everywhere the cable modems have been rolled out, they have been a big hit at first, then a  failure.
What the cable companies will not tell prospective customers:
1) Cable modems work off the ethernet principle. up to 1000 homes in a neighborhood can be put on a hub. The 10 mb speed is only if no one else is on the system. So, if there were 100 people using it at the same time as you, take 10mb/100 to get 100K which is slower that ISDN.
2) Security is a real problem too. Any kid with any experience or anyone  for that matter, can easily see what is being sent/received. Spoofing IP's is easier. Also, you dont have a static IP address.
3) Customer service. people generally get lousy customer service from cable companies, do they want to their business to rely on a company with known lousy service?
4) Reliable service. cable service is sometimes irratic, especially during storms. Can they do business that way?
5) No focus. To be a strong reliable company, you have to have focus, do one thing and do it well. Cable companies are not good ISP's. They have higher turnover in people because they get bored and technically unchallenged.

Hope this helps, I'd like to hear what others say.

David Perdue,
CEO
ACCESS    http://www.accessllc.net
Jr. Voice: 901-797-3142
Fax: 901-797-2802
3915 Mendenhall Road S.
Memphis, TN 38115