Also, clutch pedal effort is more dependant on your cable, quadrant, throwout bearing, bearing retainer, pivot ball and cable adjustment than the clutch itself, imo (other than a centerforce). Also, length of inseam play a big part in the perception of pedal effort, as well as calf and thigh muscle development, and blood concentrations of estrogen. I, for one, find my King Cobra clutch to feel MUCH lighter than the one in my great-grandmother's Mazda 323.
My KC started out light. It didn't take very much pounding before it got real, real heavy- not to mention having to toe it to the floor to get it to disengage. No complaints with my SPEC though, still feels great and way better clutch for the same money. Like Blk92 said though, there are many other parameters that effect how it feels, and most of it is how you set up the linkage.