Best: Bruce Springsteen was the best.

Other Great ones: Eminem, Prodigy, Steve Angello, Mumford & Sons

Worst: Not anyone really. Possibly Paolo Nutini, but it wasn't his fault as it was at a festival and I couldn't really hear anything as everyone was shouting around me. I was annoyed because I'm a big fan of his. To be honest everyone I've seen has been worth watching.