To be honest[around here at least] DSL speeds stay pretty much constant.
Cable speeds can vary different times of the day[depending on how many users are on your line].
I've played with both and use DSL.
I can easilly afford cable,but why?
The extra cost is a waste and what usually happens is your firewall and A/V protection programs negate any differences anyway.
Save your money.
Most of the computer techs I know are on DSL up here.
That tells me something.