A couple of points that I am sure most of us all realize. Nothing man made on a production line is always going to be trouble free. There is also nothing to say that 2000 rounds from now your trouble free pistol is still going to be trouble free. Things can and do break but I think the thought here is that most of the teething problems have been worked out. Every new weapon design has some. Another thing to remember is that each letter added to the serial number chain is another 10,000 pistols, what are they up to now, M or N? That is a lot of pistols, some of which are seeing a lot of rounds going down the pipe. If a reoccuring problem was showing up I am pretty sure S&W would be on top of it and get it fixed. So far no recalls posted on their website for the M&P. Another thing to realize is that the internet forums are a great place to share information but one needs to remember that many users get on a forum to fix a problem they have. They usually post their problem before talking to the dealer they bought it from or the manufactuer that made it. A couple more then get on that thread saying that their junk pistol does that too. Sometimes from there a minor tuning or adjustment problem becomes a huge errornet problem. Remember that 10,000 guns per letter and say we're up to the Ms, that is 130,000 M&Ps. If you took even 1% of that, it would be 1300. You don't have 1300 members here screaming their guns aren't working. Being that it is human nature to condemn and complain more than praise, especially on the faceless errornet, and you don't see that many people here having problems that aren't getting fixed or figured out. I'd say you can buy a M&P with confidence.
I have 2, one to carry and another by the bedside for my wife.