I have Verizon DSL and it's satisfactory, but not great. I have used AT&T Cable before and it was much much faster, but that was also because it was in the Middle of No Where, Ohio, so not many of my neighbors were sucking up bandwidth (cable speeds are dependent on how many subscribers there are).
Basically, it's pretty dependent on where you live. My DSL service in Pittsburgh has been a pretty constant 768 bps (~100 kb/s dl speed), but that's capped and doesn't go any higher, whereas with the cable modem in Ohio I got up to 300 kb/s when the connection was good and no one else was on.
Bottom Line: I would get cable over DSL if they had it here, but you may want to check on someone who has cable near you to see how much near saturation point they are around you.