Just to clarify, I never said that I had problems. I said that problems had to be addressed by the factory (or authorized Armorer). Meaning that I could not fix the pistol myself. For example, I wanted a different trigger configuration. The pistol had to be shipped back to H&K because there was not an authorized Armorer in my area. As I see it, that's a problem! The Glock is much different. I can do everything on this pistol myself.I might have to call a friendly BS flag on the USP .40 having issues.
I say that because while I am admittedly an M&P fan (owning several of them) my first love has always been HK. I have an HK USP .40 in my collection that has a date code of 98 or 99...I've never had issues with that pistol (save for the occasional ammo issue due to my reloads). It's like a tank and works every time I take it out to shoot and more importantly I can nail 4" circles of steel at 20 yards with somewhat regularity.
Recently I decided to swap to a match trigger and that made all the more fun to shoot. This was not a "needed" upgrade as I could shoot the USP just fine in its stock configuration, it was more about want.
I guess, everyone's experiences are different as highlighted by your experience vs mine.
As for the glock being this simple tool everyone keeps referring to, it's peaked my interest. I've never really considered the glock simple nor the M&P, HK's I own complex. So when referring to the simplicity are we talking strictly internal components or overall function? From my perspective the M&P is no more complex than the Glock, but like I said I'm a fan so I'm biased.