I would "mirror" Paul's comments. The Darton CPS cam is probably the smoothest (barring round wheels) of the cam systems currently available....but it is not the quietest (unless some Sims equip. is added).

A Mathews Straightline Maxcam I or II equipped bow is almost as smooth and much quieter (bare bow)....followed closely by any Hoyt Excel cam equipped bow....

...at least in my experience.