I'm on the £9.99 BT deal at home and have no problems with it all all. The trick is no not use the crummy BT dialer software but to set up a new Dial-Up Networking connection that only dials the 0800 number. I've had absolutley no problems with them at all since May when I joined.
I've sufed the Internet since before the World Wide Web existed (yep, all gophers, ftp's and telnets) and have had the 'fortune' of trying a shed load of ISP's.
I've heard that NTL's 24/7 service is good, and may check them out.
Aq
PS: My day job is Tech Support Manager for an ISP. Not BT or NTL I might add...!