Everybody has different experiences with ISPs. Personally, I would rather eat my own right arm that return to the clutches of TalkTalk or PlusNet. They really didn't seem to give a monkey's when they screwed up and left us without a service for days on end. Currently I have BT Infinity. It's not cheap but it seems to be fairly reliable so far.
We were with Virgin (after they took over NTL) at our old place, and had no problems at all, until they were pointlessly obdurate when we moved house (about keeping our email addresses). We changed to BT then, and have found the service pretty reliable (I can't remember the last outage, and the kit seems ok).
The biggest problem is that they're a bit monolithic - when our BT Vision box packed up, I tested it by plugging into other, known working aerials, established that it was f***ed, and called to ask for a replacement (we'd been customers for about 7 years at that point). They wouldn't replace it without sending an engineer (meaning a day off for me) and if said engineer couldn't find a fault, would charge £150. I told them to get stuffed, and bought a Humax PVR (we were only using the service for recording TV in any case), cancelling the TV part of the subscription. They have their procedures, and don't make exceptions.
The phone support is terrible (ime), but their live chat is pretty good, and both times I've used that, have had good, knowledgeable service.
Plus Points: Reliability, no traffic management (or at least, none I've discerned), decent kit supplied.
Minus Points: cost, lack of flexibility, you'll pay for a lot of bundled extras that you may not use.