Glad I jumped ship last August,no way would I have had Sky BB
I've had Sky for a year now.
It runs at line-speed 24/7/365. When I've phoned up to get someone to manually reconfigure the line (the DLM system has "issues" on short lines) it has been done within 10 minutes and without jumping through hoops. I would note that I never call before 9am or after 6pm as the chances of getting script-monkeys increases dramatically.
My experiences with Sky broadband support have been CONSIDERABLY better than Be's support, who are (IME) totally useless if there's any sort of real issue.
On the flip side Sky aren't a company who even pay lip-service to looking after the average customer - I'm talking TV/phone/BB here. If you never contact them then you'll stay on outdated/uncompetitive deals.
They also push firmware to routers which has resulted in several major problems in the last 9 months. You can use other routers easier now as Sky seem to have had to allow normal CHAP logins (they use MER on ADSL usually) to accommodate the FTTC customers piggybacking on the BT FTTC modem.
Would I recommend them?
No.
Would I say "avoid with a bargepole"?
No.
Sky's BB is exceptionally good in most of the UK provided everything is OK on the line/internal wiring. Their support is very variable (avoid forums like the plague for example) but that's the same for all the major ISPs.
Caveat emptor as always.