Nick Mason is better than Larry Mullen in a number of ways. He was never a great technical drummer, but he had his moments (see the intro to Time, live versions of A Saucerful Of Secrets, Up The Khyber, One Of These Days.) He knew the meaning of subtlety, something Larry Mullen doesn't know very much of these days. Larry approaches the drums with the point of view: "I hit things and people clap." (A joke, yes, but with some truth to it.) Nick was the opposite. A sort of, "I hit things and create art." He never outshone the other members of Pink Floyd, but he knew exactly how to work within their music and compliment the melodies. He didn't just tap out a beat that the other members of the band played over. He knew that a drumset could be used to simulate a heartbeat, a gunshot, whatever. Larry utilised the same ideas from time to time, but there isn't anybody quite as good at it as Nick.
While it has nothing to do with his drumming, Nick Mason is also a better people-person than Larry. He is always happy to greet fans. He doesn't rush away from the arena as quickly as he can to avoid signing things for the fans who provide him with his money. He's friendly, he's funny...just a really nice guy.