Been with BT FTTC for the past ~5 years. Don't have a reason to complain about the actual service provided. Always had the full 80/20 - but the cabinet is right outside my house so I'd hope that would be the case.
Had issues with the HomeHub wifi performance but since moving to a 3rd party router it's been great.
Just finishing a fixed 2 year contract (through retentions) and now moving to Pulse8.
Main issue was with the new price, customer service and dubious practises with "extras" they provided for free for 12 months then start charging you for (I don't regularly check my bills).
Hopefully moving to Pulse8 who have simple contract, no initial term special prices, no unwanted extras that I'm paying for (cloud storage, bundled router etc.) and hopefully better CS.