Hogue Grips for all
I recently purchased Hogue rubber grips for my M&P 15 Sport and my S&W model 411 3rd generation pistol in .40 S&W. I've always felt the stock A2 grip on the M&P was too skinny for my hands. The Hogue grip is just about perfect. I also purchased a rubber butt pad for the collapsible stock, as it adds just enough to the length of pull with the stock extended all the way.
The Hogue grip on the .40 cal. keeps the pistol from slipping and sliding when my hands get sweaty on those hot Florida days. Never felt like I had that great of control with the stock plastic grips.