I own two M&P 9mm FS models, and one Pro.
Pros - very reliable (under 1 stoppage in 2k rounds average,) excellent ergonomics, good triggers out of the box, good factory and aftermarket support.
Cons - accuracy is inadequate for a defensive or competition pistol. My minimum accuracy requirement for a defensive pistol is 2.5" at 25 yards from a solid rest. My M&Ps will do around 5-6".
If 5-6" at 25 yards is good enough for you, then I can't recommend the M&P highly enough. I'm hanging on to mine, at least until the Apex/Bar-Sto barrel comes out.
-C