I own a M-9, which I enjoy, and after reading this argument, I got mine out and decided to do a little test.
I put a primed case in the chamber and pointed the gun in a safe direction with my left hand. In my right hand was a rawhide mallet (you know, one that would not foul up the finish of the gun but still have the hardness to simulate a drop on concrete, roughly).
I proceded to smack the rear of the slide and the sides of the gun. Nothing happened. I then shifted my grip and whacked it in a few more spots, such as under the rear of the grip. Still nothing. (I did not hold back my blows. I hit it very hard.) I have concluded that the drop safe work as designed.
That said, I did notice, when I removed the slide (prior to banging the gun around) I did notice that when the pistol is uncocked (the trigger is pulled) there is no stopping the firing pin from moving forward. This could be construed as a problem, but when are you going to experience a loaded chamber with the striker down on a striker fired weapon? Pretty much never.
Cornbread2 and Macman, I hear your argument, and commend you both for your observations. At first glance, I agreed with both of you and was shocked to find no plunger type firingpin block ala Glock on my gun.
I decided to take a risk and experiment on the gun, for the benefit of us all. On my gun, the safe systems work as advertised. I hope this helps.