We've had BT for several years on Bb. Always found them very good.
Only had one problem, a mistake was made when we moved 2 years ago which meant we lost our Bb connection 5 days before we moved and had to use dial up. When I phoned them they immediately apologised for the error and credited my account with £40 as compensation.
Helpline when troubleshooting has been very helpful too (hence the name "Helpline" I suppose), even though the only times I've used it the problem has been down to something daft I've done at my end.