Allow me to present a very short dissertation on brake feel and performance:
There are three variables involved.
- Lever force
- Lever travel
- Braking force
The ideal brake would perform as follows: Braking force would be linearly proportional to lever force and would reach the maximum needed (enough to flip the bike or slip the tire on dry pavement) with a reasonable force on the lever. Lever travel would be zero.
In this ideal brake system, braking force would be totally independant of any other variables, such as time, weather or how hot the disc/rim was or whatever.
My sidepull calipers are pretty good in the dry, they deliver all the stopping power I need with a reasonable amount of force on the lever and not much lever travel. In the wet, they are much less linear, and the braking force is also related to time spent squeezing the lever - after the pads clear the rims, they work better.
My mechanical road discs perform well, wet or dry, with one weakness - too much travel. I can still get all the braking power I need, with much less lever force, but the lever moves almost to the bars. The relationship between lever force and stopping power seems more linear -- I think this makes them "easy to modulate".