It depends on the area you live in. The technologies vary by region and service providers. In my area cable is at least twice as fast on the download side. I have about 15 clients with one of 4 services, Cable, Business cable, DLS and Business DSL. The Business Cable is limited to bandwidth and seems to be about a 4th of the cable speed. I can’t tell the difference with Home vs Business DSL. I have run bandwidth tests on Home DSL vs Home Cable. Most of the time the DSL run tests in the 1-2 mps The Cable accounts are usually 4-7. Mine is always at the top of the scale. Here is a utility to test speed.
http://www.bandwidthplace.com/speedtest/

I just ran it 3 times (the free limit) and received 7.3, 7.3, and 7.5.

Most DSL setups have you using a logon session process. This takes more time to log on to get started after a reboot (or log on if you are using NT, 2000 pro, or XP pro). The installation of a inexpensive cable/dsl router will fix easily stop this delay.

Reliability will vary with area and distribution lines. Are you cable and telephone lines buried and more protected from storms?

Get what works best for you area. Get some input from your local PC users group. Pricing will make a difference by market. If you already have cable TV, you may get a discount. Promotions will make a difference as well.