I use the slide stop/release. There's a reason why, with a proper two handed, thumbs forward grip, that you've got a digit parked right there to work the control.
I don't consider it a fine motor skill on a properly designed pistol, but I do think the vogue for slingshotting has something to do with the poor design of the factory stock Glock slide release. If you lack the fine motor skills to sweep your thumb downward, I'd question if you have the fine motor skills to find and engage a trigger.
Slingshotting (or any related technique), on the other hand, involves a lot of unnecessary movement of the non-firing hand. Time spent grabbing the slide instead of just flicking the slide stop/release is time that could be spent driving the gun back onto target and engaging.