I've used both Cable and ADSL. Haven't had many problems with either. I had ADSL with PacBell and now I'm using Cable with @HOME. (In Fremont, CA) There are a few annoying quirks with each.
I always had perfect connects with ADSL, never been dumped or had any bad connection problems. I only had DSL for about 6 months, in that time it went completely down twice. The first time it was down for about 3 hrs, the second time it was down for about a day. Other than that I didn't have any problems with it.
I also have very good connects with Cable. About 2 times a month it seems to go "down" but only for 5-10 mins usually. I've never been dumped except once when this "outage" happened. There is also 1 very very annoying thing with cable, every once in a while someone will steal my IP address and I will get an IP conflict. (this has happened twice) They don't put any ACL's on the modems that restrict what IP you can use, so really anyone can grab anyone else's IP address. (we get static IP's) This is more of an annoyance than anything else, but it does prevent you from using the service. Talking to their tech support really doesn't help, it's very difficult for them to do anything about it. (I have 2 friends who both work for @home and apparently this happens a LOT)
As far as bandwidth is concerned I get quite a bit more downstream on my cable modem than I got with ADSL. On DSL the fastest I could download was about 180Kb/sec, on Cable I've gotten over 400Kb/sec but that is quite rare.
Of course all this has just been my experience and is not representative of all DSL or Cable internet service. YMMV

Overall I've been very happy with both. I got DSL because it was the only thing available in my area. After I moved to Fremont the only thing available was Cable. I would suggest you get what is available, either of them is 100x better than any analog modem. Cable also cost 1/2 as much to install and cost me less monthly than my DSL service did.
Hope this helps,
-Funky
[This message has been edited by Funky (edited 03-21-2000).]
[This message has been edited by Funky (edited 03-21-2000).]