The M&P may be just a hair smoother (at least mine) but the FN has a stronger more positive trigger return/reset.
Congrats on the new pistol.
I have a FNP9, its a fantastic shooter.
I wonder about the comment conserning the trigger on the M&P. I have M&P9 Pro and the trigger leaves a lot to be desired. Are you saying your M&P had a better trigger out of the box, or after installing aftermarket trigger parts?