I like disc brakes and have them on my MTB. But my rim brakes will lock up both tires just as well on my road bikes. So with the tires locked up on my MTB I can stop in half the distance that I would be able to if I lock my tires up on the rim brake bikes? Brakes are brakes. If they'll lock up the wheels the stopping distance is going to be the same. Or am I missing something here?
Edit-The main thing I like about disc brakes is that I won't have to replace the rims because they're worn thin.