FTTC can be very good but can also be bad.... the ISP you choose is very important.
The infrastructure itself is fine but ISP's have seemed to struggle over the past 6-12 months with capacity on back haul & at data centers..
I started my FTTC experience with Plusnet... that was a bad hoice, speeds went bad, packet loss and to cap it off a lack of customer service which didn't help the matter... I had to involve an ombudsman in the end to get the contract killed off.
I believe things have got a little better at Plusnet but still some issues... I would avoid them for fiber 'currently'
I then switched to Zen (through their own network not BT's) that was great but after a couple of months they too started having issues on their back haul which I believe are still ongoing... I left them too...
Currently I've been with BT for 3 months and that's been pretty good.... (better than I expected)... Had a couple of issues with there Hub 5 and customer service isn't too great but with my own router and using my old Openreach branded modem it seems to work very well, I have done many speed tests during the time with them and only witnessed any single thread speed reductions 2/3 times and that was only losing 20-30 meg and wasn't consistent... so wasn't the same in the next test.
The only other provider I would consider right now for FTTC would be Sky... however their Terms and Conditions don't allow use of 3rd party routers and their current hub is a bit entry level, it's possible to use your own router but I 'think' their is special requirement's and can be tricky to set up.