I prefer not to share my jurisdiction and what agency I am speaking about on the internet, but I just discussed at length with one of our officers who serves with a roughly 300-strong agency. He told me that the agency is switching away from M&P 40 fullsize after 3-4 years. He stated they have had multiple firing pin breakages and light strikes, and after a recent OIS they started evaluating all their systems. They are sticking with .40 since they're a highway-focal agency and the vast majority of their contacts involve traffic stops, but swapping to the Gen 4 longslide Glock .40 (I believe it's the G35?). Before the M&P40, they had Gen 3 Glock 22s for about a decade. I guess the general consensus after a few years with the M&P is that this agency missed their Glocks.
When I was examining his M&P (very tolerant officer putting up with a gun nut prosecutor) it looked like they issued Winchester PDX1 or Ranger Bonded. Wonder if there's a primer issue.
Just an interesting data point, may mean nothing but I thought I'd share with you guys. Interesting that the full-size .40 has always been the M&P that wasn't really a problem child.