I can only relate my limited experience with one Gen 3/G19, and four Gen4's; a 17, a 35, a 34 and a 19. All the the GEN 4s have been flawless for my brother and I so far.
That said, there are too many Gen 4 stories to dismiss the concerns. I know that Glock will not rest until all the issues have been completely addressed, as the future of the company relies on it 100% I expect that most of the issues have already been resolved, and now Glock is now on the long road to rebuilding it's reputation for extreme reliability.
I am curious how many Gen 4 owners WHO HAVE TAKEN POSSESSION OF THEIR GUN IN THE PAST 2 to3 MONTHS are experiencing the GEN 4 problems that have reported? Those who have the most recent RSA's, that is.