We will discuss rim brakes, since they are most prevalent on folding bicycles. Nowadays all brakes are V-brakes, which are easier to adjust & modulate. The best V brakes move perpendicular to the rim, motion in different directions will minimize efficiency. They should be cold forged from aluminum ( CNC machining is weaker ), with a frame that minimizes flex. Shimano started the V brake idea, but everyone has quality V brakes nowadays. Our Tektro brakes are quality cost effective calipers.