Being a sucker for anything S&W, I put my dealer on notice that I wanted the first one he got in back in November. Fast forward to late February, I finally got one.

The M&P has a polymer frame that is stiffened by a stainless steel internal chassis. After shooting , it really feels closer to a steel framed pistol than any other polymer gun I've fired. The trigger will remind you of the earlier Sigma in appearance only. It is much lighter and crisper in actual use. S&W lists it at 6.5lb and I would guess that's about right. It is smooth with a short reset and is easier for me to shoot more accurately than most pistols outside of a 1911. Speaking of 1911's, the grip angle of the M&P is a lot closer to the John Moses Browning design than the obvious market rival of this new pistol..the Glock.
Here is a detail pic of the slide, some machining marks are visible, but they are even and not noticeable unless closely examined:

The 15 round magazines are very nice and have functioned flawlessly through the first 250 rds or so, using every kind of ammo I had on hand. They are marked for .357 Sig also :

Field stripping the pistol is straight-forward and addresses the issue of sear deactivation in a manner other than pulling the trigger. This will most likely appeal to PD's as a way of preventing ND's (negligent discharges).
First, lock the slide back and remove magazine, then depress the takedown lever, flip the yellow sear deactivation lever down to the position shown and release slide from frame. The recoil spring/guide lifts out and the barrel will slide out of the frame.All pretty standard stuff except for the sear deactivation.

To change the grip panels, remove magazine, turn grip tool 90 deg (either way) and remove, slide grip panel down and off, install new panel and reverse steps :

In closing, the M&P is ergonomic, well-made, points and shoots as well as any polymer gun I've tried and holds 15 rounds in a package than can be tailored to a wide range of hands. Assuming long term durability is good, S&W should sell a boat load of these. It would be great to see a large percentage of PD's go back to an American made service gun, and considering the Army's M9 is probably on the way out, the stakes may be even higher.