Before today, I had not shot a Glock in maybe 15 years. I bought a SIG P228 in 1991 and never looked back. However, earlier today I had a chance to try a Glock 22 .40 cal. side by side with the SIG P226 .40 cal. that I acquired last year.
Frankly, I was not impressed by the Glock. It felt slippery in my hand, it failed to feed twice in less than 10 rounds, and it was generally harder to shoot accurately. Furthermore, I am not really a fan of the .40 caliber round. Until today, I didn't really like my SIG in this caliber. That was before I tried the Glock. Now I finally like this SIG!
Sorry guys. Maybe the Glock in 9mm would be better?
Gaston Glock designed his pistol around the 9mm (9x19) round. The Glock did not transition well to bigger bore and/or higher pressure rounds. There is a long history of problems with Glocks in .40 and .45, some to include catastrophic failures. This is well documented. From what I understand, Glock has "corrected" the defeciencies of pistols in those calibers that were allegedly the cause of those types of failures.
I carried a Glock 17, and then the 19 since the late 80's. The 19 is hands down my favorite and the best in the line. I have since found what I believe is the best striker fired polymer framed pistol for the money available. That is the S&W M&P.
The differnces between the M&P and the Glock are substantial. The M&P has a stainless steel chasis imbedded in the polymer to impart rigidity and give the roll pins hard mounts. Glock no. The M&P has adjustable grip size. Glock recently with the Gen IV, which are having other problems. The M&P comes with decent sights out of the box. Glock no. The M&P is ambidextrous. Glock no. The bore axis ratio is less on the M&P than on the Glock. M&P has a loaded chamber "viewer". Glock no. M&P is available with a 1911 style manual safety. Glock no. One of the paramount differences is the M&P was designed around the .40 S&W round, and has had no issues transitioning to other calibers to include 9mm, .357 SIG, and .45 ACP. Oh, and it is made in America by American workers employed by an American company.
The M&P had a few minor growing pains early on, but Smith and Wesson really did their homework with this pistol. I would not hesitate to carry a Glock 19 again, but think the M&P is a superior side arm on several fronts.