The only ISP I've had consistly good customer service with is Sky, Virgin's not too bad but theirs alot of lieing that can go on and also some other issues which Virgin are currently investigating.
TalkTalk... attempted once....
BT... hard to get anyone that knows anything, always ends up with a complaint being raised before any help is made available.
Unfortunately Sky wasn't suitable for me, and BT is the only ISP that FTTC seems to work well on... IE. Capacity seems good.
Anyway, getting off topic, for those interested I will be running a Q&A for the new Smart Hub from Thursday all being well... I'll be starting a new thread for it, so keep your eyes peeled if interested.