I have a full size 9 that is one of the first batch guns. I bought it at a really reduced price from a range that was going out of business. I think it was $100 bucks with 2 mags 10 years ago. I think I have more in Bianchi leather for the gun than I do into it.
I have not shot it a bunch but it hasnot failed. I don't shoot it a lot as I have 2 sig's in 9 and one in 40 that I shoot better. But I have used it when taking customers to shoots and it has never failed to fire, feed, or extract.
The only problem I had with it was one of my friends went to a steel shoot with me and wanted to shoot it and stuck it in his holster not use my leather and popped the front sight off.
If you have $600 for a hand gun don't get a Glock get a Sigma, plastic holster, spare mag or two and a lot of ammo for the same $600 as the Glock. You will be able to shoot the gun at a steel or IDPA shoot for the price of owning a glock.
To you that own glocks. Good for you. I'll stay with my sigma Same bang for less bucks