I have been a plusnet customer for about 5 years, always on 12 month contracts with my own router.
I live in a remote area so have particular problems with speed and generally I have had to sort those out myself excepting plusnet eventually admitting they had initially imposed a 1Mbps cap on the circuit citing excessive errors. Now I have been running just over 3Mbps for a few years partly due to rewiring the house and partly due to router tweeking using DSLSTATS.
I have experienced very few problems caused by plusnet, at my speed there is no apparent traffic management, minimal service outages (maybe 2/year) and back up in an hour or so. Costwise they have always been ready to undercut whatever other quotes I get but I think you have to be prepared to do your research to get this service, I have just renewed for line rent only with weekend and eve calls inclusive, unlimited bb, very good :):):) the one downside is call waiting times on there support line but hey i only have to use it once a year!!
overall happy satisfied customer :)
Ohh I dont use any services so plumped for 5 in the middle.