sure they are great they can carry more cargo/passengers and they are more fuel efficient
(My boldface). I'm not sure that's been the case with the 380. From what I've heard, it's a gas gobbler when compared with (not a hell of a lot) smaller aircraft that carry (not a hell of a lot) less payload, like the 777-300ER. Someone will surely correct me if I'm wrong, but from an fuel economy point of view, it would seem not to be an ideal ULH aircraft. It seems to have been designed to be economically optimal at around a seven hour stage length.
As for pax comfort: I'd have to agree with
A 380-800 driver. It's very nice. My only complaint is that it's so damned quiet, if someone's snoring loudly up to five or six rows away, he soundblasts the whole damned cabin.