I'm going to have to agree with the polymer frame idea. Another thing I think *might* be at issue is durability of the polymer frame. One of the demo models at my local gun pusher... I mean dealer, was starting to show wear in the area of the upper leading edge of the grip. It seemed like the slide was contacting it somehow and was beginning to fold it back so that it was sticking up and could snag on things. I also didn't think the trigger was on par with my Sig 228, but that could just be that mine's broken in.
And no, I'm not a poly pistol hater, I'd be more than happy to buy a glock if I could just find someone local to me selling one.
I'd also say that the standard "P serries" (226, 220, 228/9 etc) are probably seen as more reliable or durable due to the fact that they have military/DOD contracts.