I was with Virgin for the past year, and while I have heard plenty of horror stories, I actually had no major issues myself with them. If they’re your only option for superfast, then you may as well go with them.
I have since switched to Hyperoptic, as I had always planned to, but they were not immediately available when I moved in, so Virgin was a stopgap. It was either Virgin or standard DSL, Virgin won out!
I’ve posted these in another thread somewhere before, but in terms of reliablity here is an average week of hourly speedtests whilst I was on Virgin (I was paying for the 200Mbps package)
Just for fun, because it’s not overly readable, but here is ~a year’s worth of hourly speedtest results:
So the speed can be a bit uppy downy, but it averages out to be more acceptable than DSL, and I had not major outages.
That said, Hyperoptic has been much more consistent in the provided service, paying for a 150Mbps up/down service, and on average getting slightly higher. Here are the last three weeks of hourly speedtests: