In reply to edhawk21:
Some one I used to climb with eons ago reckoned that the key to a good route was the distance from which the line could be seen and desired from. Think of the view to High neb buttress on stanage from Miles away, the soaring Millstone aretes from Hathersage, the lines on the Cromlech from the pass and Cioch nose in Applecross. In short, if a line looks compelling from over a mile away, its unlikely to disappoint.