Hi Derpy,
I've done some digging myself and confirmed the following (apologies if you already know this):
Both BT and Sky use the same Openreach network, same network teams and routing etc, so the quality of service shouldn't be any different between the two.
That's not the case.
They both use the same Openreach access network but that's the only thing in common.
Beyond the OLT/L2S in your local exchange they are completely separate networks.
BT uses Openreach to the exchange then they use BT Wholesale backhaul network to get from your exchange to BT servers in London.
Sky use Openreach to the exchange then they use their own backhaul network to get from your exchange to their servers in London.
Completely separate routing and completely separate network teams, apart from Openreach controlling between the home and exchange for both
Different quality of service.
In most cases, BT will often carry out the initial installation, providing the ONT and Sky will supply their own router. Where the installation is very straight forward or you already have FTTP, a visit isnt usually required or sometimes a Sky engineer may attend themselves.
BT will usually survey the installation to agree where the fibre will enter the property and agree this (within reason).[/li]
[li]with Sky, you are free to replace their Hub with your own router (I have a UniFi UDMP myself), however by doing this I think you'd loose the VOIP calls feature. No biggie imo, most of us use mobiles.
Both mentions of BT here should be Openreach.
BT don't do any surveys or ONT installations.
Sky do indeed do some ONT installations.