If I had to rank them it would probably go something like Schilling, Mussina, Brown, Glavine, although the first 3 are essentially interchangeable.

Like Brown, Mussina was screwed out of a Cy Young award. In 2001 he had a sizable advantage in WAR and was best in ERA+, yet finished 5th. Of course Glavine was never screwed out of winning because A) he didn't have many monster years and B) he had the recognition from the trio with Maddux and Smoltz.