I am happy with the MagPul BUIS that came with my M&P Sport. Since I added an Aimpoint PRO to my carbine it saved me the expense off adding a low profile back up sight. I practice with it folded down and the PRO set at 6 or 7, as well as extended with the PRO off. Finally got everything dialed in where they both shoot to the same point of aim. However, I am more accurate with the Aimpoint. I with S&W sold the Sport with a 20 round mag and optional 5 round limiter for hunting, but most folks would rather have the 30.