Not concerned about the so-called Revel power issue. This is one of these "I heard on the internet one time..." kind of statements.
Actually it's not. I've owned two pairs of M20's and one pair of F30's. It has nothing to do with what I heard on the internet. It has to do with personal experience. And me saying that Revels require more than average power to sound their best.
Of course the Manley sounded better than the Arcam. If you are going to compare power ratings, compare two of the small quality level.