Interesting. As a result of the information in this thread plus the Brownells sale, I just bought some 3rd generation Pmags (no window). They will probably turn out to be the best quality magazines I own for my rifle, and after verifying function, they will probably be kept in reserve for serious use as I wear out other magazines I previously purchased in training and practice. At the same time, I bought a 3 pack of Glock 19 Pmags, also on sale. The whole point of that purchase is to keep some of the wear and tear off my more expensive OEM magazines during training and practice. So, for one weapon, the Pmag is the nice magazine that gets preserved as long as I can, and for the other it is the inexpensive one that takes the wear and tear.