I had a 96% uptime with VM broadband when I lived in an ex-Telewest area. Longest downtime was 6 days. 6 fucking days. I must have rang the fuckers 20 times.
It was incredibly unreliable and I was stuck with the fuckers for a year. Much like the post above, their Indian support were terrible. Truly shit. I gave up calling because I would spend 30 minutes waiting for them to slowly winding their way through the scripted crap they call a decision tree before they realised it was not my equipment but it was their unlocked, wide open to the weather, street cabinet (held together with insulation tape on a few occasions).
I have not had a single second of unscheduled downtime with BT after > 2 years on Infinity 2. Yes, it goes down after midnight now and again for maintenance, but never during the day. Yeah there will be people who have no problems with VM and people who have had a bad time with BT ... but VM just suck balls at support.