I have 2 M&Ps -- a Shield 9mm and an M&P 22 Compact. The Shield is my every day, all day carry, and the 22 Compact I bought for fun and to give my wife some confidence shooting, since she's never been a fan (or any good). We both like that one, and she can hit paper with it!
Since I read so many complaints, I just wanted too say that my Shield just passed the 1000 round mark, no problems of any kind with all kinds of 9mm ammo I've accumulated over my shooting life. It feeds whatever I grab from the ammo pile, and there is a lot of variety in the collection. The only things all the ammo has in common is that it's all brass cased and all new (not re-loaded or remanufactured). I have WWB, S&B, Remington, Federal, Speer, etc., etc.
My M&P 22 Compact just passed 500 rounds with the same story. All the ammo is 40 gr. round nose, but other than that, it is of all makes...some lead, some coated, some copper plated, but just plain old 22LR, all makes all prices, some bulk, some not. I have never even had a FTF, which can be pretty common in a 22 semi pistol, with cheap ammo.
So to all the haters, please don't buy S&W. If you have one and you hate it, sell it. Then buy something else and go on their forum and bitch.