Just finished the "home" trigger job and it does make a dramatic improvement. I personally feel my trigger pull is still a little to stiff, so rummaging through my goody box I spied a standard 5# Glock striker spring. The Glock spring is significantly lighter than the stock M&P, and guess what else? Yep, it fits perfectly.
This also dropped the pull weight,then I seated several new primers in an empty case to see if they would ignite. They did and the primer striker is very good.
I must caution I have not function tested yet, therefore I am not recommending this.