I've had a bunch of knives from both Civivi and Kizer's N690 selections. I've had all of them apart for cleaning and inspection. I've used most of them and the others were gifts. (I like to make sure my gift knives are 100%, clean, and lubricated with good non-toxic stuff.) Overall, Civivi is better on fit, finish, and QC. I only had one issue with Civivi. I got an Elementum with a real wet noodle of a detent. Turn-around time on the warranty was longer than I wanted so I just exchanged it via the retailer.
Kizer is definitely decent. The ones that are good are very good. Of the dozen or so I've had, three had issues. One had a chewed up polymer washer. It was assembled with six washers, two bronze per side with a thin polymer washer between each pair of bronze washers. I'm not sure why they made it that way but whatever. I contacted Kizer for a replacement. They sent me a full set of replacement washers and that was nice.
Another knife had corrosion on the inside of one of the liners. It worked perfectly and I only noticed because I had the knife apart. It was dark pitting as opposed to rust. I don't know if it left the factory that way or if something happened during overseas shipping. Either way, it still worked and looked fine when together. So I kept it and still sometimes carry it.
The third was a liner lock with very early lock-up. As a result, it is possible to overcome the lock with moderate spine pressure. By "moderate", I mean more than I would ever want to apply to the spine of a folding knife in the first place. It's just that it isn't supposed to be like that. I could have returned it but it was a limited edition. I may eventually get around to fixing it but for now, I just treat like I do any folding knife: a knife that can fold.