I have both and after shooting them side by side I prefer the Shield. You can use the flush fit magazine if you want, but 8 round mags are easy to get and cheap without going through the hassle of getting extensions.
IMO the trigger on the new M&Ps is better than the Glock triggers.
I have shot both and agree I agree 100% with this. The Glock is a good pistol too, but I prefer the S&W.
Pros for the Shield: Greater magazine capacity, price, real steal sights, and the Shield also has a frame safety if desired. Some people dislike the safety but it is unobtrusive, positive, and there if I want to use it for chambering, reholstering, or shooting with the kids or newbie shooters.
