I recently received my 5" PC Ported Slide kit for my FS M&P9. At first, I didn't notice the difference in the striker block but certainly felt it during dry fire. A quick visual comparison shows the PC version is rounded vs "chamfered". Here's the required pic. On the left, my original FS slide (purchased in 2013), the right, my PC slide purchased a short while ago.
Hopefully, you can see the clear difference.
And what a difference it makes. The "staging" feel is completely gone. I also had what felt like a double reset. First, the trigger bar slides off the SB, then the actual reset. Also gone.
I also installed the "H" stamp trigger bar. I previously installed the "improved" slide stop.
The range had a 2 hour-ish wait since it's Father's Day so you'll need to wait for a range report.
Happy Father's Day to all!!!