Like Gary, I have also bought heavily into the M&P series.
I have:
M&P9
M&P9c
M&P40
M&P45
The 45 is my latest acquisition.
I've got the most rounds through the 9. It has not failed once and is truly a sweet shooter.
I also own Glocks, 1911s and Sigs. The M&P replaced the G19 as my daily carry, although I still carry my G19 as a truck gun.
I agree with Gary's claim that the M&P is the best striker-fired polymer on the market.
In all fairness, I did have a problem with my 9c. I didn't experience the
same magazine release issue that others did, but it did revolve around the mag release. The release was binding badly and often the magazine would not lock into place. Rather embarrasing to be carrying concealed and have your magazine kerthunk on the floor at the local hardware store.
I called up Smith and Wesson and explained the issue. They emailed me a UPS overnight prepaid label. I boxed it up and sent it back with a letter expressing my disappointment.
10 days later the gun returned to me, fixed, and sporting a set of night sights that weren't previously there. Needless to say, I was very happy with the service I received.
In addition, I have been told that our local Sheriff's Department (Madison County, AL) has switched from the Beretta 92 (9mm) to the Smith and Wesson M&P in 9mm. I haven't verified that yet, but that's what I've been told.
Lots of good information over on the
M&P forum, including many of the problems that Sturm mentioned.