Can you clarify which models you mean?
For example... M&P can mean anything from a full size, down to a single stack sub compact, and sizes between.
But as others have said, pick one that fits your hand well, and you like the trigger on... For CCW, smaller means easier to conceal, but harder to shoot well.
That being said, my M&P shield shoots very well for a small single stack 9mm...
My M&P compact shoots almost as nice as my M&P full size.
The PPQ has a wonderful trigger and feels good in the hand, though is a little large for CCW, but it can be done with good gear.