I'm going to risk saying that probably less than 10% of brake problems can be attributed to the pads themselves. The remaining 90% is the grind, condition of the surface of the rim, pad setup, brake mounts, booster, bleed etc. You can even mess up the braking performance by grinding a rim incorrectly.
edit, Oh and if Steve says that he gets his Coust compound from Michael then that's the truth. If there is any difference between the so called original Cousts and HSB Cousts (which is actually only a rumour since I don't think anybody has performed a direct comparison) it can only be attributed to Michael Coustelliers actions.