I have three M&Ps.
The first is an M&P 40 compact. It has had one failure to eject and one failure to feed in 9200 rounds. It also has had half a dozen failures to fire, all of which could be attributed to me pulling the trigger before it reset. Failures to fire have never occurred any time I consciously released the trigger past the reset point. Thus, with only two jams not attributable to operator error in 9200 rounds, my 40C has demonstrated near-perfect reliability, along with excellent accuracy. It is my primary carry gun.
The second is a Shield 9. Its first two recoil spring assemblies were defective, and it took me over three months to get a good one. It has decent accuracy for what it is, but it's not nearly as accurate as my 40c. It also has been very picky about ammo. It had 23 failures to eject and 4 failures to feed in its first 3800 rounds -- way too many for a carry gun. When the Shield .45 came out, I rented one and found it to be vastly superior to my 9. I ended up buying a .45 in February, and the 9 has been on the shelf ever since.
Finally, the Shield .45. Despite being delivered with a misaligned front sight and occasional nosediving failures to feed, the .45 is better than the 9 in every way. The sight has been adjusted, and it is now as accurate as my 40c. A feed ramp polishing, along with broken-in magazines and the careful loading of them, has ended the nosedives. It has never had a failure to eject in its 2200 rounds. My Shield .45 is now reliable enough to carry, and I have carried it quite a bit of late.
So now, I have two excellent M&P carry guns to choose from, plus one mediocre M&P safe queen. Two out of three is fine with me.