Ah, yes--the old Sigma-bashing. Maybe it's because I've shot and instructed on DA revolvers for a long time, but it seems to me that S&W intended to duplicate that experience in a semi auto as closely as possible. I bought a 9mm Sigma about two years ago for grins, and found to my delight that it not only fit my hand very nicely, but I could shoot it well, particularly at speed. It's very quick out of the old kydex and frankly the trigger weight is no issue at all. I've been shooting 1911s for decades; have used BHPs, Glocks, SIGs, and all the rest. The Sigma could be better looking and have a proper rail, but it feels great, is reliable and accurate (and stock). I shoot it better than Glocks (which I loathe) and better than I ever did a SIG. I have to admit that it's better than I expected, but that just helps to make up for some of the guns I joyfully offloaded.
Have only fondled the M&Ps and SDs but I prefer the trigger of the Sigma. It's not a draft horse (1911) or a show pony (BHP) but a nice little Morgan.
The best part is that the adverse commentary on the Sigma's trigger really helps keep the price of nice used ones down.