When BT goes wrong , it is awful.
When it does not go wrong, it is fine. My 50 mega whatnot connection is normally fine, and when guests & kids are here and we use lots of mega gigas streaming tvs etc, all works fine.
Their most recent attempt at a con on me was when something went wrong with their line. I called. They said that if the problem was mine, the engineer visit would cost UKP130. Fine, I said. They sent out an engineer, (the very next day). He said that the problem was theirs, and he fixed it.
My connection from the modem/router is about 6 feet from their main socket in the house, which is about 1 foot from where their line comes out of the ground. I told them that the problem was most unlikely to be mine.
So on a bill some 2 months later they wanted to charge me for the visit!!
Irate phone call to Accounts - which was to a Brit person in a Brit place, and charge was removed.
I hate to think what they get away with, especially with folk with less time than me, or with folk who assume that any big Co can be trusted...............
On the other hand, when I worked for a mega-corp and bought their global services, (for millions, but millions less than their competition) they consistently out-performed the Japanese and USA competitors. Pings KL to Tokyo better than my pings to London!! Maybe that's why their Corp services lost bucket loads of money.