I was a Plusnet subscriber until about a month back. Worked perfectly with 65Mb until someone (kell yComms) messed with the pole outside and the speed dropped to about 4mb. Plusnet booked an engineer who then cut me off totally (Kelly again), and he only turned up after 10 days. Took a further 12 days to then get an Openreach guy out who tested my line, and said there was a break in the cable "42 M away", so at the pole. He fixed it, and Plusnet then tried to tell em they needed to get another engineer out to fix the line "properly" before they would put my speed up. This would also cost cost me a chunk of money "If no fault, or a fault with your internal cables was found". The idea that the Openreach guy had already resolved the issue, so no fault would be found, and I'm not paying out the suggested couple of hundred quid for nothing seems to fly right over their heads.
They did promise to also pay me back some cash for the service I had been unable to use. that didn't happen either.
So now I'm on Virgin, who are relatively cheap, relatively quick, and while their CS is a bit poop I expect it.