I know it's been awhile, but I have something to add.
While waiting for my M&P .45ACP to arrive, I have borrowed a P229 .40S&W. Let me first say how much I love this gun. However, my first day on the range with it involved a few FTFs, usually on the first round. I only had one mid-magazine FTF. Easy to clear - bring slide back, punch the mag out, and clear the jammed round. During cleaning, I polished the ramp. That did not help. Today, I was looking even more closely, and noticed that the stock magazine is not fully seating. There is a good 1/8 inch between the mag base and the bottom of the grip. I can push up on the mag, and it works perfectly. I assume that, during fire cycling, it will feed properly, as long as I support the mag base with my left hand. I was only given one magazine, and will ask the owner if he has another. The mag looks beautiful (the gun is barely used). I don't know if there is a way to adjust the mag release button to provide a solution.