I shoot my full size M&P 9 in IDPA, USPSA, and 3gun. It us also my go to carry gun. A friend I shoot with at all the matches has the Pro, and it is almost identical tk my full size. He has the Apex kit installed and I had my trigger work and slide work done by this guy, http://ateiguns.com/
At the 3gun matches here, I see a lot of guys, and girls, using Glocks. I also se several people using M&Ps. It is all out what gun is going to fit you better. After I picked up my M&P at my local gun store when they showed it to me, I told them to put it in the safe, its mine. It just felt like it fit my hands perfect.
I don't have any issues with Glocks I have just never really shot them. I shot a 195 once when j first started shooting 3 or so years ago and didn't like the grip but have thought about trying one again.