I've been with Plusnet for over 5 years and up until this year the service was fine.
Since May I've had problems with my line, dropping every 5 - 10 mins at times, and very low connection speeds. I know all network have problems at times, but the PlusNet response has been terrible.
They do answer the phone quite quickly, but their focus then seems to be on moving the support issue on to some other internal status - they don't seem to focus on getting the line actually fixed! When I took this up with them they claimed that they are giving good service as each time they move it from the current status to another which resets their support metric clock, so its always being worked on. I tried escalating the issue to Plusnet management, but could not get them to respond.
My advise is if depend on your ADSL line don't use an ISP which does not have some target measure of the time to fix a fault.
I have been happy paying extra for the Plusnet service believing I would get higher level of support. This is not the case, the support staff are not able to arrange to resolve issues in a reasonable time frame (5May until today and its still not fixed...)