I know your frustration with the M&P trigger precisely. My full-size 40 was driving me absolutely bat**** prior to sending it off for a trigger job. My grouping was horrible and I knew that I was doing everything right in terms of minimizing trigger jerk.
The thing is, some of those guns have a even more horrible break than others. My compact isn't like that and neither is my wife's compact. But the big 40 would literally jump to the left every time the trigger broke over and as a result my initial shot might have been off but my follow-up shot would definitely be off.
After the trigger was re-worked by Dan Burwell and the pull weight cut down to around 3.5lbs, the gun became a nail driver. If I miss now, it's because I screwed up.
If you were closer, I'd be more than happy to let you shoot it sometime at the range. That trigger feels almost as good now as some 1911 triggers do out of the box.