Things change over the years, but, in the 80s when I was still working, I had more customers bring average guns (Winchester 94s, Marlin .22s, etc.) for me to "fix." This was in the days when Woolco (Woolworth's discount chain) sold guns.
Invariably, I would disassemble the guns, find nothing wrong, test fire them with store ammo, and have perfect results, only to find out they had been using Federal ammo which was the bottom of the barrel on those days.
I advised against the use of Federal, and they never had trouble after that.
It was my policy to remind people that Federal was supplying to the U.S. govt. and the govt. always buys from the lowest bidder.
Fast forward to the mid 90s, when my adopted son, who is a sheriff, acquired a .44 Mag Desert Eagle. As we were test firing it about 15% of the loads would fail to fire, due to the trigger not functioning. As it turned out, these were Federals, and while I was looking at the non-fired rounds, I saw that the rim thickness was grossly oversized, which I confirmed by measuring with a dial caliper. The incorrect rim thickness was actually causing the disconnector to not allow the pistol to fire. I don't remember the exact figures, but it was considerable.
OK, this was between 20 to 30+ years ago, and I do admit things can change, but this was my experience with Federal ammo, and I have never had any faith in it.