If the answer had to be as short as this, I believe it would be ADSL. There are a couple of strong security and reliability advantages in xDSL compared to Cable, coming from the fact that each subscriber is physically isolated from the other.
There is a good article
on Cable at the site. For a similar introduction at xDSL you would have to query a web search engine for phrases such as "how does dsl work?". Also try "adsl VS cable" for comparison articles.
For more specific information regarding DSL, there are some amazing posts from Ranger24 at
My view is that it isn't as simple as which is best. Depends on where you are (geographically), what you want to do, and who the available suppliers are.
Firstly the country you are in makes a diference as the quality of telco & cable networks varies from country to country. For example in the UK I'd take cable over DSL anyday because our telco network (copper pairs to the house) is terrible. Most copper pairs used are still the copper installed by BT years ago and the quaility of copper varies greatly, along with the distance from the exchange (500m to 4 Kms).
Meanwhile the UK cable network has in the main got ggod quality copper within 500 -1Km of each of the supplied houses - resulting in a more predicatble and reliable service.
Also Cable networks are going through an upgrade cycle at the moment makeing reliable speeds of 15 - 20mb a realistc possibility, while ADSL2+ speeds can vary between 2 -20mbs (with 23mbs occasionaly)
The suppliers of services make a difference as different suppliers have different network policies and 9traffic management that could mean a great looking service is useless because P2P is actively managed to 2kb/s .
i will agree with ranger on this issue.
but do bare in mind that adsl will give you 85% of the promised bandwidth all the time depending on how far away you are from the exchange, but cable has contention issues which fluctuates between 100% to a mere 25%. i have worked with a ISP which provides internet over cable, and they had this problem.