My problem with the anti-spall/frag coatings is that while they may work OK when it's only 1 or 2 shots, but when the bullets come at you in MULTIPLES, they probably don't work so well.
Count yourself lucky if it's only 1 or 2 shots. I don't count on luck . . . .
Case in point - watch the video of the Dallas officer who was murdered when using the pillar for cover and was flanked . . .