A little google foo, showed a color change and a Viking Tactical Fiber Optic Night Sight Package, a slight trigger job, a slight change to the finish, and ....other than a standard full size .40 (which I own and love), I see no other reason than to keep the M&P line current, and offer a slightly tweaked model. (Not a fan of the color, but alas,....)
Who is in charge of marketing at S&W?
It was at the NRA show, but not offered at the S&W site....Hmmmmm.....