I see AK malfunctions once in a while. Hard to compare them against the AR's because:
1. I don't see as many AK's
2. Most folks that own AK's don't go swapping out a bunch of the op system parts
I ran an Arsenal Inc AK for several years. It was no more or less reliable than my Daniel Defense M4. I believe I see more issues with the cheapo AK's than I do with the "top tier" guns from firms like Arsenal.
If I have a 20 student carbine class, I'll have 12-15 students running AR-variants. The rest will be a mix of AK's, SCAR's, Tavor's, etc. I did have a student in a recent carbine course whose SCAR kicked the bucket right out of the gate. I don't remember the issue. He switched to his SBR AR and ran it for the next 2 days.
The only AK I ever saw have an issue in a carbine class was mine, and it was the mag. The spring crapped out on it.
Great info in the OP, and regarding the ARs, the only change I generally make is to add the LMT enhanced carrier, and that is just for reducing the gas to run suppressed. One of these days, I'd like to try an adjustable gas block, but the e-carrier works well, and it's a minimal change.
Btw about 5 or so years ago, we were both in one of USSA1's AK carbine courses down by the airport. There was a little contest at the end for some swag, and you and I were paired off toward's the end (final 4 I think). You beat me by a split second. Easy access to training classes is one of the few things I miss about living in Atlanta...