While I've done reverse-grip shoulder presses before, I never really felt them a lot in my delts, which is why this lift is a game-changer. It's basically like the regular grip version of the scrape the rack press, but your palms are supinated or facing your body.
Try it and you'll probably be surprised. It'll give you an amazing delt pump. It emphasizes the front delt a bit more than the normal grip version, especially at the top where you get a tremendous peak contraction.
Go for more volume (8-15 reps) on this reverse-grip variation. And before you ask, nope, this doesn't work as well in a Smith machine.