What timbo said is 100% correct? This has always been a debate as to which is faster & the one constant was the fact that it depended on where you lived.
I live in NY & where I'm at my cable blows away DSL but others I know in other parts of the country say the opposite. I would do local research as that will give you the best answer.
Some will say the company I use for cable internet access is the best in the country speed & price wise & I'd have to agree but the thing that makes it work is the fact when they see alot of people on one node they cut it to make new ones so it doesn't get overloaded & we all can get the best possible.
As I said do some local research & also visit
www.dslreports.com
It is a great site I frequent as it has reviews, forums etc for tons of broadband providers not just DSL & your company might just be there & you can ask for yourself. I'm on there alot checking in with Optimum Online personally.