As a left handed shooter, I have not had any trouble with my M&P 15-22, I have owned it for over 2 years and put close to 2K rounds down range with it.
Keep in mind that the sights are about 2 inches above the barrel. Any aimed shot that is real close is going to be low, no matter how much you adjust the sights.
I used the Hogue Handall Jr for my M&P 9C. It was very tight but it fit on with a little Windex. I had to cut about 1/8th of an inch off the bottom so I could get the magazine in. This could work on the M&P 22C.
I got a Shield for my wife last year and I was planning on getting a Shield 40 for myself. I take my F/S 40 to the range at least once a week and my hands are really used to the feel of the double stacked magazine. When it came time for me to buy a Shield of my own , I no longer liked the feel...
Last year when I was in the market for a Single Stack 9mm Glock put out a 380, so the next month I bought a Shield and am happy with it. Glock waited too long and I have have 3 other M&P's to go with the Shield.
I shoot my full size 40 at least once a week, so the Shield feel too thin in my hand to enjoy shooting it, but the Shield is easier to carry. I suggest getting both a M&P9c and a Shield.