MediaOne claims that that is the case with their service. But some cable providers, particularly ones with less experience in the Internet business or ones that are trying to minimize costs, may deliver wildly fluctuating speeds, depending on the time of day, and changing as more people sign up, with the worst case being prime-time speeds that are as slow as dialup. If the service is not set up with proper safeguards, it is possible for other people in your neighborhood to use the cable line to access your machine. Once again, the important factor is the experience and professionalism of the provider. Established providers, like MediaOne, reportedly have routine procedures in place to provide the necessary protection.
Costs also vary widely from one provider to another.
But typically, DSL costs more, especially for startup. In most cases, cable customers are already customers of the cable company. They have a cable connection to their home, and this is just an add-on service, which the provider can make very attractive with a variety of special deals, bundled in with their TV service. They may provide the cable modem the same way they provide the standard cable box, as a rental that is invisibly buried in your monthly bill. Cable and DSL also differ in terms of their target markets.