Just some comments from a nerd. I did look up the NATO specs the other day. Got tired of not knowing what they really meant. Very old. Glocks were supposed to be designed to meet NATO specs. So they were originally designed for between 108 and 128 gr bullets. Most rounds used would likely have been 124 gr so I assume this is the sweet spot. The pressure ranges stated however appear to be higher than what I see listed for +P loads. So while 115 gr is well within the NATO spec the pressures and energy of less expensive rounds would be lower than NATO. And since any recoil operated pistol is likely dependent on the bullet weight and the internal pressure to cycle the slide, any change from the sweet spot could change the speed of the slide coming back, which affects how the case is ejected from the gun. And of course you can limp wrist it and add another variable to the equation.
I would also assume that a lighter pistol, such as a polymer Glock (and other makes), might also be more prone to limp wrist problems since the polymer frame has less mass to stabalize the gun. But then again it is really nice to have a light pistol for carry.
As for the popularity of Glocks. Seems like they are very popular at this time since a couple of weeks ago a Glock rep told me they had over 600,000 on backorder. Most larger gun stores, including Gander Mt and two Bass Pro Shops I visited recently had no glocks at all.
From --- happy with my Glocks