Personal experience as well as posters over on the AK Files. There are tons of horror stories over there. Personally though, I picked up an SLR104FR from Nate / Little Jack's back in 2014 or so and it was fantastic - barrel components straight as an arrow and a beautiful finish, and it came with a 30rd Circle 10 magazine. I got a 106CR a few years later and it was okay but nothing like the 104 - canted components, finish that wore off if you looked at it wrong, and a dinky 5rd magazine. It zeroed fine and ran fine, but at $1.2k I was expecting more, like the 104 I had bought previously for less money.
I got a 106F in 2019 and it was absolutely garbage. Every barrel component was canted (RSB was canted left, GB left, FSB right). I noticed this at the FFL, but I run AKs a lot and it's just part of the game - as long as they zero, they're fine. So, I took it to the range to zero it and it was hitting all over the place - couldn't even get on paper at 25 yards. It was to the point where I'd consider it completely unsafe to shoot. Many WTFs later, upon closer inspection, the front trunnion itself was installed crooked, so the barrel was also crooked. Combine that with the canted barrel components and it was basically a disaster. I had multiple people look at it and nobody noticed the crooked trunnion until I popped the dust cover and gas tube off and told them to look down the center of the rifle. It was hard to see when everything was together, but once you broke it down and saw it you couldn't un-see it. I missed it myself at the FFL - now, I don't care how long the salesman has to wait, I'm inspecting an AK down to the disconnector spring.
