In my experience comps work until they don't. If you shoot a variety of ammo, you will have issues. If you find the ammo that works and only shoot that ammo, you will be in good shape.
This is from my AAR of the Kyle Defoor class I just attended:
My Glock 19 with the Zev Barrel and Primary Machine Comp was the same setup I used for Modern Samurai 2 Day Appendix and Hilton Yam’s 2 Day Red Dot. I had run Winchester 147gr NATO in the first class and Bobcat Armament 147 and 124gr, some Winchester NATO and some Federal 115 in the second class with no gun issues. This was about 800-1000 rounds on this setup. I have also shot 124 gr X-Trem copper plated bullets that I have reloaded with 5.3 gr of Unique and Winchester standard small pistol primers through the gun when testing ammo. I had replaced the factory recoil spring with a 13lbs recoil spring when I initially built the gun. I started Kyle's class with Bobcat Armament 124 grain, approximately 3 mags full, and switched to PMC 124gr Bronze that I had bought a case of to take the class. I had mixed one mag with PMC and Bobcat Armament as I ran out while loading the mag before class.
I started the class with no issues other than my poor shooting due to failing at the red dot fundamentals I had learned from two of the best in previous classes. When I hit that 4th or 5th mag loaded with a mixture of rounds the trouble started. Once I hit the PMC the gun would stovepipe every round to every two to three rounds. The ejection pattern changed from 3 o’clock to the right and behind me to 12 o’clock forward in front of the muzzle. The slide had recoiled enough to the rear to load another round and cock the striker, but it was catching the spent round in a 12 0’clock stovepipe. When I completed a malfunction clearance, I would get a live round along with the spent case that was stovepipe. This went on for the rest of the day until I switch to my Glock 22 to finish out the last two hours of class. I was not happy losing live rounds in the grass at the current prices. Kyle said it and I knew it; it was a comp issue. I got to say the fateful words, it has always worked before. I got home that night and removed the comp from the barrel, returned the factory recoil spring to the gun, and went back to class the next day. I can say with confidence, that a comped 9mm shoots a lot softer than a stock Glock 22 40 cal.
The next day I had zero gun issues and completed the class with my 19.