Through no choice of my own I actually saw McFly do a few songs live over the summer, and they really rocked, I was amazed. They can play, and their songs a good solid tunes.
The problem is listening to their studio work, unfortunately it sounds like they have a pop producer, as opposed to a producer who usually does bands. The production ruins all of their good work, if they just turned the guitars and drums up, and roughened up the vocals to give more of a band feel, than a pop act feel, they would go down much better.