Sportsman STOL, on 67 172H reduced all low speed negative handling effects by 10 to 15 mph. with 650lb in it the aircraft flies solid at an indicated speed between 43 to 45 mph, it used to be unnerving below 60 mph. Extreme changes in VX angle and VX speed, I would estimate on the average it took 100ft off my landing distance. There was also a large improvement in aileron response below 60mph. No effect on cruse speed.