Joe,
I changed from Virgin to Talk Talk about 4 months ago.I'd had no problems with Virgin over the 4 years I'd been with them, but Talk Talk saves me money. With Virgin I paid about £15 per month for the broadband service but line rental and call charges were paid to to BT. Line rental works out at about £10.50 per month +vat with calls extra. I don't use the phone much so I was paying around £15 per month to BT for the privilige of having their phone, then £15 to Virgin for the internet service.
With Talk-Talk you don't pay line rental to BT. You pay the same line rental and call charges to them (Talk-Talk) and about £5 to £6 for your broadband connection. So I'm getting line rental, phone calls and broadband for about £20 per month instead of nearer £30 per month.The system actually rids you of paying BT for their phone line. Hope this is all making sense.

Regards

Andy