I bought my 5" 9 Pro in March 2011, and it sat until November 2011 when I started shooting it. It is at 10k rounds now. Like any other pistol it has its quirks and things I like or don't like. Before the M&P I shot a Glock.
My biggest gripe is that the springs do not seem to be as durable as Glocks. I now replace the mag springs in the three primary mags that I use every 3k rounds through the gun, so roughly 1k rounds through the magazine. With the Glocks I could change them once a year in the same conditions, and it was good; in the M&P it needs mag springs a lot more often. I've also had a handful of light strikes with Tula primers (known for their hardness) which never happened with the Glock either, so I think the striker spring either doesn't have quite as much oomph, or once again, wears faster. But really, only about 4 or 5 total out of 9k or so, is fine for practice. I have taken to using Federals for sanctioned ammo, no problems.
Other than that I have not replaced any parts at all involuntarily. Stock trigger and sights are working fine. My offhand groups at 30 yards are not particularly stellar, but no different than I did with my G34, so I don't have any reason to say the pistol is not "combat accurate".
I've actually been plesantly surprised with the finish; it is holding up just as well as my Glock's. The black will wear off of contact points, but I have not seen any rust at all.
I do wish the mags were plastic coated like Glocks, and I wish they had just used pushpins for the frame like Glocks, but neither of those are really deal-breakers for me. Overall I think they have a winner.
I hope to get my hands on an FNS as soon as they come out with a 5"+ model.