I have a KZ-45, purchased slightly used in November of last year. I recently passed the 4,000 round mark without a single malfunction. Most of the ammo has been my reloads but I initially test fired it with a variety of factory JHPs: Federal 230g Hydra-Shok, Fed 230g Classic JHPs & Fed 200g +P EFMJ; Speer 200g +P Gold Dot and Blazer 200g JHPs; Winchester 230g Black Talon, Win 230g XTP & Win 185g SilverTip; plus several varieties of Mil Surp Ball and commercial Ball.
I was so impressed with the full sized KZ that I ordered the Compact version as a daily carry gun. It has now digested something over 600 rounds with only one ammunition related malfunction - a piece of brass (reload) broke off and stuck in the front of the chamber preventing any other rounds to chamber all the way. Once I saw it and cleaned the chamber it continued to function flawlessly.
Besides the weight advantage and slight capacity advantage over Government Models and Commanders, the KZ line has a couple other advantages. There is no plunger tube to loosen as it is moulded into the polymer frame; the ejector is a fixed part of the stainless sub-frame, not a staked in part; and the external extractor does not need "tuning" like the traditional one. Also, during a long outdoor shooting session in the desert sun the KZ slide got so hot I could barely touch it long enough to chamber a round. The polymer frame stayed comfortable to the touch and I continued to shoot in the 100+ heat. I hadn't thought of that as an advantage until that day at the range.
Oh, concerning accuracy, I managed from prone to put 5 of my H&G #68 handloads into a 4.5" group @ 50 yards, and my middle aged eyes can't see 4.5" at 50 yards.
If something should happen to either one of these KZs I will immediately order another one to replace it. I consider it about the best 1911 pattern weapon I have owned in over 30 years of handgun shooting.
YMMV!