My first M&P's rear
and front sights were improperly installed - off center. Easy enough to fix if you've got the tools.
SOME guys find that the triggers are gritty, or too heavy. The Apex DCAEK kit will give you a trigger that's as good as the old wheelguns. You can just shoot
most of that out, too, but it'll take a few rounds. Swapping trigger springs between the DCAEK kit from Apex and the stock springs plus a bit of polishing of contact surfaces on the trigger bar (don't forget the top of the "flag" that operates the drop safety and serves to reset the trigger bar after firing) will do a wonder for the gun. DO use Apex's sear and sear spring (swapping the sear spring pretty well demands a plastic bag). You can also install their drop safety easily, but some people have had issues with trying to remove the rear sight to do so. Follow the instructions, though!
Install a RAM kit if your model can accept it, too.
I'm an 1911 guy who started with K-Frame wheelguns back in the late 60's, and find the M&P's (I've got a 9C, 40C, and 40FS) about as comfortable to shoot as my old wheelguns. The 1911 is a tad different, but the M&P's aren't too different if you ignore the trigger take-up. (If you've got a Para LDA, the feel is almost exactly the same. A couple pounds of trigger for a bit, and then a four pound trip zone. You can set up your own trip weight within a narrow range, too.
Overall, if I didn't have a mountain of money in 1911's, I'd carry an M&P just like I did those old K-Frames way back when.
However, like 1911's, you can't have just one

....
Regards,