So I've recently brought these two frames back from the dead (both found @ the scrap yard in various states, and brought back to life with my parts bins and help from the local bike coop).
First - the rockhopper.
This is mine. The pads are kool stop Eagle 2 dual compounds. The pads are pulled from my T700 touring bike, so probably have a few hundred miles on them.
The setup works VERY well. The bike stops dead with the levers at half travel.
Meanwhile - the hard rock, I've built this up for a friend, to be her school commuter. (She currently walks 2 hours a day to get to campus).
It stops. But not nearly as well as the rockhopper. It has new Salmon Koolstop Eagle II pads.
The only thing I can think of is the little "wedge" at the end of the Eagle II pad is more worn down on the rockhopper, enabling more pad contact. Otherwise they are both using old dia-compe road levers, new cables & housings etc.