They're all as bad as each other. By which I mean that any of the ones I've ever used have been fine, and I've never had an issue with either EON or currently EDF.
I'll never go DD to save £5 a year because I'd rather have the money in my account than theirs, but other than that I just choose the people with the cheapest tariff and away I go. Everyone says that BT, Sky, TalkTalk, Tesco, Ford etc are all shite as well, but then if you have a lot of customers you're going to get the vocal minority rise to the top.
Actually, scratch that. TalkTalk areawful.