I have 5598 rounds through my Gen 4 Glock 17. I replaced the capture recoil spring early on (after 200 rounds) but I did not have any issues with the stock spring.
Since my Gen 4 was also an earlier model, it did not have the newer "dot" connector. I ordered a replacement through Glock Parts. Trigger weight is more in-line with Gen 3's now.
I have not experienced any stoppages that I did not induce (snap caps). I run an Insight M3X light on my gun. I've fired:
-115gr, 124gr, 147gr
-FMJ's, JHP's, Plated bullets
-Factory loads, Military loads, Commerical and my own reloads
If I do my part, it will shoot properly. YMMV.