I watched the guy that came in 1st in CDP in my last local IDPA match "powerstroke" the slide and miss.
Last weekend I watched 3 out of 5 "powerstrokers" do the same thing. When they come up and over the gun to pull the slide back, but are in such a hurry they don't get a firm grasp and have to do it again.
Mike Pannone was not a fan of this technique, as I was using it circa January 2014 in his class, and he told me so. He said you come too far off your master firing grip, and it's slower than using the slide stop/release. Pat McNamera on M4Carbine.net said he's seen 2 people shoot themselves in the hand doing the "powerstroke".