Shot one yesterday. Gun was brand new I put about 250 through it after the owner put a couple hundred through it. When it started to get dirty sometimes it wouldn't pick up the second round in the mag. No issues other than that. I was impressed and will be purchasing one very soon.
My GSG1911 was going strong after 30,000 rounds fired, and only had a couple of parts replaced. The replaced parts and reasons are listed here:
Barrel bushing: The original bushing from my 1st gen gun broke after a couple thousand rounds. This was a known issue and was replaced with a real steel bushing by ATI for free. They all have steel bushings today.
Recoil spring: I replaced the recoil spring twice if memory serves, but that is expected when you shoot thousands of rounds through any gun.
Firing Pin: The firing pin broke simply due to the high rate of fire (~12,000 rnds) and is considered a wearable part like the springs. It was replaced by ATI for free and they paid shipping both ways.
Barrel: The threads where the barrel retention screw holds the barrel in place were stripped by me over-torquing the screw (~15,000 rounds). Even though it was my fault, ATI replaced it for free. Great customer service!
I sold my GSG1911 to another INGO member after passing 30,000 rounds while the gun was still going strong, and it was as accurate as day-1. It also had very little signs of wear, with the exception of the dust cover of the slide where it contacts the frame, which is very normal. There was no peening or visible wear on the alloy slide or rails.
I will be buying another once .22 ammo becomes available again. I used to shoot more than a thousand rounds a week, but that ended when the .22 ammo craziness began.
Here is an durability and accuracy review of my GSG1911 from a few years back, when I could stil by ammo for it: