I've certainly seen issues with Glocks - but they are typically related to ammo, magazines or technique, and can nearly always be corrected with some attention to mag springs, recoil springs, or ammo.
For the vast majority though, they are as you state - dead nuts reliable.
Yeah. When I pick up a Glock, I know it will go bang.
I will correct myself though to say that I have heard occassional complaints about failure to cycle, but that has never happened to me, even once.