Just took my new M&P 9mmL 5in Pro Series CORE pistol out this past weekend. No FTE's, no FTF's issues at all shooting 250 rounds. One thing I did notice was twice it failed to lock back. I have to say this was the shooter. I was holding the pistol with right thumb over right hand and close to the slide lock. Low and behold, my right thumb was resting on the slide lock keeping it from engaging on the last round. I moved the thumb over about 1/4in or more and no more failures. I was also able to reproduce this on a 92FS as well. Just my observation and maybe it will help someone else.
I installed the Trijicon RM07 6.5moa, love this pistol, very accurate. Next purchase is an APEX trigger and a couple of Taran extended base pads.