After watching videos of several successful deployments on the companies website, including ones that relied on the suspect being "startled" to allow officers to close, I am not a fan.
It will work in some specific situations, and sorta work in others, but I don't think it brings enough to the table to justify an extra piece of equipment to train on and carry. It also appears to be another pistol shaped less lethal that an officer can reach for and grab a gun instead. Taser's already have that role covered.
Get thee back thy Good Idea Fairy!!