Woa, was just listening to one of the Knebworth shows and realizing how much better Roberts vocals are than in 75 and 77. I consider the weakest point of the show immy, aldo he's actually pretty good and only here and there e makes a mistake or "forgets" where to put his fingers.
People say he was a bad player by the end of Zeppelin, but i never thought that way. Obviously he was too high on heroin and got blinded for a couple of notes, but he was still the one and only Zeppelin axeman.