In the old days, when frames were slender, boosters reduced the deflections in the tubes when the brakes were applied - meaning less wasted energy and better braking.  I have a Zoo Pitbull now and there is so much much more tubing, plating & welding, particularly in front of the brake clamps, that I wonder whether a booster is really adding anything.  I am not currently running a booster and the feel of the brakes is ideal.  Does anyone notice a sigificant difference with or without?