I have them on my personal gun and my duty gun. It is an exceptional product. The myth about them not being as precise is just that. I can hit a man sized steel target at 110 yards consistantly with them.
XS sights or 600 rounds of practice? Which helps more?
Over the life of your carry pistol? The sights.
Seeing your front sight is important, especially in no- or low-light, which is when most violent encounters take place.
Obviously they're not a replacement for training and practice, but they really should be on a serious defensive handgun. (night sights in general, not just XS's offerings)
Keep in mind, they are meant to be a "combat" sight, meant to get on target quickly. Some say that aren't as precise as typical sights, but
YouTube - XS Sight Demo II
YouTube - XS Sight Demo