I love the M&P design and love my 40 Compact. After a few hundred rounds the trigger smooths out really nicely - wonderful trigger indeed! And the ergos feel awesome. Great design & concept overall. Well supported chambers, accurate, feed & eject reliable.
But mine is unreliable due to mag drop problem. Mine is a recent production "N" version. All was fine for about 400 rounds, then the mag started dropping on almost every round. S&W took back the gun, replaced the mag catch and sent back to me. All was fine for about 300 rounds when it started happening again. This time they sent me another (3rd this time) mag catch which the CS rep told me was the very latest they had (now with a hardened metal engagement tab). The new mag catch didn't make it through two full mags before the dropping started again.
It is not true that S&W has corrected the mag drop problem on the M&P's with their revised mag catch. They are apparently trying to figure it out and have released a new catch (which looks no different to me. And hasn't eliminated the problem in my gun.) I urge you to spend some time on the mp-pistol.com site to learn more about this.
Regardless of the true percentage of M&P owners with mag drop problems (it is 19% on the UNscientific poll on the site) - S&W has a definite problem with mags dropping and in spite of some supposedly revised mag catches (I can't see any changes myself in looking at them) the problem has not been eliminated. Great gun design in every respect except the mag catch area. I just wish I could trust mine, but so far I can't. It's going to be going back to S&W again. S&W customer service is excellent and they seem to be trying hard to correct this known design flaw. If you decide to buy one.. just be aware of the potential for mag drop reliability problems after the gun has seen some wear and tear... many of the M&P's are reputed to run just great (so far), but the potential for mag drop problems does, unfortunately, continue lurk.