I used to be a fan of the Serpa holster. However, the more and more I used them the more problems I had. I don’t recommend them to anyone and suggest just about anything else over the Serpa. A brown paper sack is preferable in my opinion.
Problems I’ve personally seen:
1. Failure to depress lock mechanism completely, which results in the pistol not releasing during a quick draw.
2. The gun being jerked out of the hand somehow, resulting in a draw stroke that ends with the gun being tossed away from the shooter.
3. The lock failing and ending up with the gun being stuck in the holster.