Glad you love your SU-22. I'm awfully fond of mine.
Who is posting bad reviews of the SU-22?
I'm not sure what you mean by "early vin model". The serial numbers are sequential, although they aren't decimal numbers. They're a weird numbering system, I think it's base 34. The first batch was supposedly 100 SU-22 rifles, and they didn't have the improved feed ramp profile to lessen the feed jams or the lower cutout on the ejection port to prevent ejection jams.
With a lot more ammo through your SU-22, you'll probably find that its reliability improves and it becomes less ammo sensitive.
Mine's been flawless for around 800 rounds. (yeah, I know Bruce, I need to shoot it more. If it ever drys up and warms up I plan on running a bunch more through it.) It will even feed Remington Goldens now.