the one factor you guys dont take into account is how well a given person can brake, and the surface and traction available.
Sure, I dont deny that the disc brakes are going to be stronger, and have good modulation, I come from a motorycycle background with some paved track racing experience and so understand hard braking.
braking on two wheels isnt like a digital on/off experience, you deal with all kinds of factors, your ability to get on the brakes fast, how hard you apply the front, your body language in terms of weight transfer, reading the feeling of traction and modulating for this while still getting the maximum braking out of a given situation--all this stuff. Comes down a lot to your bike handling skills essentially, so for those of us with lots of two wheeled experience, and braking hard at all kinds of speeds on all kinds of surfaces, there is a certain grain of salt taken with how great discs are---I say again, I completely agree that they are stronger and all in all are better in a quantative sense, but when you put the human factor in, it begins to blur the issue, because riding on skinny little tires, we are always going to getting to the edge of traction at some point anyway.
I should add that I plan to use mechanical discs like BB7s on my next touring bike, so its not like I am anti-disc, and completely see the advantage of less finger pressure on long long windy downhills when loaded. The thing is, the times we are on technical downhills that push the braking limits are far and few between, and also some people just brake a lot more than others, so end up taxing their braking system, whatever it is, a lot more than other people simply due to not being comfortable with speed and or dragging brakes a lot.