Generally speaking DSL is a better choice than cable for several reasons.
Cable
1) Shares the physical medium with all your neighbors who also have it. This immediately exposes your computer to theirs and vice-versa.
2) Because the physical medium is shared, there is no way to control how the bandwidth is being spread out. Simply put, it is possible for one person on a node to kill the performance of everyone else on that cable.
3) The physical medium of cable is not required by law to be maintained. I have a sheared cable in my back yard which has been that way for a year.
DSL
1) Sharing of the connection occurs in the telephone switch, which is load balanced so all users get a fair shot at getting service to the packet.
2) Because their is no physical sharing of the medium, you are instantly protected from the immediate visibilty to your neighbor.
3) The physical phone line is protected by law and phone companies are required to keep it maintained within specific time periods. The time period varies by state, but is generally around 24 hours for response time (residential line), less if it is a trunk line.
Given the same speed and equal price, DSL is usually the better choice. However, the ISP is also part of the equation. This is where things tend to break. If the ISP does a poor job, the physical choice of which medium to use becomes moot.
