I haven’t seen them, but I’d like to see more of the science behind it. It seems to me it would detract from developing your ability to aim with traditional sights. I suppose the same could be said for a laser sight. Im not sure I like the idea. I feel like it would cover the view of the target. But maybe that’s not an issue within the 20’ limit. With aging eyes, I may have to start considering such contraptions.
Are you thinking of giving them a try?