With brakes, it's all about system leverage, pad (good) friction, parasitic (bad) friction, caliper rigidity, and adjustment and lubrication of pivot points.
My most terrifying braking experience was with short-reach Campag. sidepulls and Shimano pads, on a 15% descent under high-humidity, patchy fog, weather conditions. Replacing the Shimanos with KoolStops helped considerably, but it was still not enough for safety. I now have Shimano dual-pivot sidepulls (huge difference), Shimano aero levers (15% more leverage than the original non-aero Modolos), modern cable housings, and KoolStop pads, and the Bianchi is a lot more enjoyable now that I have braking confidence.
I still have the original Weinmann centerpulls on the Capos and Mafac centerpulls on the Peugeot, and those work far better than the Modolo or Campag. single-pivot sidepulls ever could, under any conditions, again because of leverage. One can also boost centerpull brake caliper system leverage by varying the length of the straddle cable, which is a trivial operation on Mafacs.
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"Far and away the best prize that life offers is the chance to work hard at work worth doing." --Theodore Roosevelt
Capo: 1959 Modell Campagnolo, S/N 40324; 1960 Sieger (2), S/N 42624, 42597
Carlton: 1962 Franco Suisse, S/N K7911
Peugeot: 1970 UO-8, S/N 0010468
Bianchi: 1982 Campione d'Italia, S/N 1.M9914
Schwinn: 1988 Project KOM-10, S/N F804069