I left Virgin because in my opinion they are over priced and unreliable.
At least with the OpenReach network (or BTWholesale) you have a choice of providers who you can move to. another provider if your service from them is poor (congestion, customer service etc).
With Virgin it's them and them only for cable for most of the UK.
Their customer service is patchy at best, and awful most of the time. I rang them on 3 or 4 occasions to explain that one of the exterior junction boxes of theirs has no cover and is exposed to the elements, I may as well have spoken a foreign language, they had no idea and no interest.
I have looked at Uno but I have been advised that "as yet" they are unable to transfer my service to them as I am on Now TV (Sky), but it's in progress for them to be able to... so I may move to them.
(changed one word to avoid the censor)
On NOW TV Broadband up to 38 Mbps