The brand and geometry (dual-pivot versus single pivot versus center pull) matter hardly at all. The primary issues that affect braking "power" in my experience are pad age/material, rim cleanliness, cable housing condition (i.e. is the lining worn out), cable condition (i.e. smoothness of finish) and caliper condition (e.g. are the pivots lubed and the spring contact points uncorroded?). Geometry makes a difference in feel and hand effort required, but not max braking power unless you have very low hand strength. Geometry can sometimes make a bigger difference if the caliper mechanical advantage is not matched to the lever mechanical advantage.