I don't use talk talk myself but know a couple of people who do. Think the service is ok but actually talking to them and sorting out problems can be a pain. They also mentioned that they or charged a direct debit fee a couple of times?!?
I've had TalkTalk for two years now and they have been fine. Never had a problem at all and they were recommended to me by someone who had never had a problem with them either. I pay for Anytime calls which is something like £4.50 a month. So no your not mad and I would say it is a good option. Just speaking as I find.
I'm with BT and they might cost a bit more, but I have always had a quick response when I've had problems. I'd rather stay with a provider who gives decent service.
Father in law uses TalkTalk never any problems. All of the ISPs have many dissatisfied customers (try googling) but they all also presumably have thousands of satisfied customers. My guess is that overall they're all as good/bad as each other. May be worth shopping around for a bargain though as cost is probably all that separates them. Just my opinion of course.......