I know it's possible to adjust MAFAC Racers so they don't squeal. Last Wednesday, I rode from Tepic, Mexico to the coast with George Otis (@cruiser here, I think), roughly 21 miles, most of it downhill. His Motobecane Le Champion has MAFAC Racer brakes. I didn't hear them squeal at all. He didn't seem to have any trouble stopping either.