I had HFC from 2020 until about a year ago, when I moved somewhere with FTTP. To be honest, in normal operation I don't really notice the difference. It was plenty fast enough. I'm on the plan that used to be 100 down (20 up I think? Not actually sure.) but got upgraded to 500 for free.

The real difference is that the ageing coaxial part of HFC used to cause it to cut out completely every few weeks and require me to restart my router, the NTD, or both. The brand new fibre is so reliable.