Sort out your pricing and customer service, Virgin
I got Virgin Fibre on an 18 month contract. It was one of those where the first 12 months were considerably cheaper than the last 6.
I have no qualms about the broadband itself - it's incredibly fast and their router seems to work well with loads of devices connected in my house which is very old - and has thick walls where some other WIFI hasn't always worked too well. So no complaints about the broadband.
But, I faced a few issues in the first 3 months whereby they never billed me correctly (using the "last 6 months" rate instead of the first 12). When I phoned them they were apologetic and credited my account. But it was the fact I had to keep telling them. Their customer service leaves a lot to be desired. Making calls - if you use their phone service on their basic fibre package - is incredibly expensive. To the point where it makes you think of the olden days of phoning abroad, or mobile to mobile 20+ years ago.
They've written to me once during the contract with a price increase - with no real justification - and a load of BS about "benefits" which are things you already got anyway.
So, as a product, it's great and I can see why people use it. But you do feel a bit shafted particularly in terms of the customer service and overall cost. I'm still debating whether or not to renew at the end of the 18 months, that's how "meh" I consider it overall.