One other comment re the PX4 SubCompact - mine tended to shoot low, even with 147 grain bullets. It was very low with 115s.
A dealer friend of mine indicated this was not unusual for the SubCompacts.
My Compact hits right on POA, and really is not much harder to conceal than the SC.
All that said, I usually carry a 1911...
One last edit: I have had zero failures with the PPS, M&P, or PX4 line so far. They are boringly reliable.