Crimson Trace LTG760 LightGuard M&P Full Size CR2 Lithium Bl

I like it a lot. Fits seamlessly within the dimensions of the frame and weighs little enough or distributes it well enough that it doesn't substantially change the feel of pointing or shooting. It also makes it easy to still have custom fitted holsters, although there doesn't seem to be a large number of premade options but I found both Galco and Alien Gear have holsters fitted to full size M&P with this light. Combined with the laser grip you get light and and visual indication of the first thing your shot will hit and it all happens automatically when you take your grip, no effort or thought involved. It really is ideal for increasing your effectiveness and avoiding confusion or mistakes if something goes bump in the night. It picks up scuffs pretty easy, although they often wipe or buff off, and if you want something to look pristine then don't carry it. I've seen no sign of a durability issue, although it is light-feeling plastic so we'll see what happens if I'm unlucky enough to have it take a real hard knock from a drop or such. As a bonus I like the way the pistol grip feels with both installed too, for me it feels better than any of the 3 normal backstraps, but I'm sure that all depends on what the dimensions of your hand happens to be.