What may be "quiet" to some, may be overly loud to others. I can clearly hear the quiet edition fans and the stock H100i fans were really loud and had the high pitch fan engine noise. I guess the noise from these SP120 quiet fans might come from vibrations. I couldn't use 3 of the fan mounting screws because they don't dig in into the screw holes on the radiator. Anyway... I can hear the noise, but it's not nearly as bad as it was with the stock fans.
I wish there was a fix for the sleep issue when using the corsair link under OSX, though. Would make things perfect.