My friend is generally happy with his VM fibre connection on the outskirts of a big city... though there used to be an issue after heavy rain which the VM customer services said was due to a damp junction box.
My PlusNet isn't great, but the last issue was with the external telephone line, which they had BT OpenReach fix within a couple of days. The thick stone walls in the house don't help WiFi, but I suspect the PlusNet modem isn't great... I should be more scientific and methodically reduce the variables, but really I should look at when fibre is coming to the street.