Much as I'd like to join the "virgin are incompetent scum" brigade, our service has been ok for the last year or so.
Maybe every two-three weeks we start getting really bad pings, but a quick (actually, quite slow) reboot of the router sorts that.
Several years ago we used to have a lot of problems which seemed to be down to a lack of capacity on their network, but touch-wood, it's been ok recently.
It seems very much a case of "Your mileage may vary".
Their customer service does suck though.
Biting the hand that feeds IT
