I ran just over 10,000 rounds through my M&P 22 full size in just under a year that I owned it.

It ran nearly flawlessly with Remington Golden, CCI Mini mags, Aguila SuperExtra, Remington Thunderbolt (though run a bore snake through every 50 rounds or it'll start to keyhole), and what little Blazer I could find.

It had about a 3% average fail rate with all flavors of Federal ammo (red box, blue box, Automatch, and the hard plastic boxes). Most of these failures were fail to feed or fail to eject.

It had closer to a 10% fail rate (or more) with all flavors of Winchester ammo including white box (333), black box (M22) and the hard plastic case stuff. I just stopped using Winchester with that gun because it was too frustrating.

I sold it and bought an M&P 22 Compact, and it has been much more tolerant with different ammo types. I've had three fail to eject with Federal Automatch, Federal Champion, and Armscor ammo. The rest of the stuff I've thrown at it have performed perfectly (including the Winchester that was so awful in the full size).

I like the feel of the full size better (I have big hands), and it compliments my 5" Pro 9mm better, but the Compact just performs so much better that I don't regret selling the full size to buy the Compact.