His gun handling was not completely terrible otherwise, either. Coulda been faster clearing the stoppage, but most people wouldn't even do that well. Can't see where his offhand thumb is.

Positioning was so-so. He had waist-high cover and some concealment for the draw, but the attacker was only two steps away from flanking that cover. Unfortunately, all of the cover in that portion of the store is very short in terms of separating one's position from an attacker at the end of the registers.

Decision to shoot was, in my estimation, not very good. It was certainly justifiable, but there were other, better options. Since his primary ethical duty is to his wife and child, he could have simply retreated to the rear and drawn, ready to defend. The guy was already on his way out, so there's very little percentage to be gained in escalating the situation in a crowded store.

If the attacker had been better-prepared, or if he had an accomplice unknown to the defender, the outcome could have been very different.

Of course:

(1) I'm Monday morning quarterbacking a situation I wasn't in, and
(2) He managed to survive the encounter.