Seems like the problems are worked out but mags are about as easy to find as unicorn poop
So far as accuracy with my M&P is concerned any problems are all me. The M&P trigger sucks! Even on the Pro Series. Interestingly enough new shooters don't seem to have too much trouble with it.
Mine has been 100% reliable. But I don't shoot it much. No fun sending ammo down range that never connects with anything.