I have one friend still with TalkTalk. She couldn't get through the labyrinth to escape, so puts up with it. She expects to move soon, and will be set free.
Our rural abode is Openreach wires or nothing. I've found them OK. When it goes wrong (and the telephone or Internet provider manages to contact Openreach - the customer can't), the team who come are knowledgeable and competent.
I've had experience of BTInternet and PlusNet. PlusNet is owned by BT, but run at "arm's length". No complaints there. I think BT has two problems: the Yahoo connection, and the script-based Indian call centre. Contacting the BT UK call centre usually gets the problem solved.