My experience...
311 / 19 red box is GOOD (shot over 3000+ rounds)
311 / 20 red box is GOOD (shot over 3600+ rounds)
311 / 14 white box is GOOD (shot about 1200-1400 rounds)
Avoid 311 / 18 if you find it. I have seen it in red box and white box. I have encountered corrosive mixed rounds with it. Not many, but enough for me to not trust that that batch is reliable, and I won't buy any boxes with rounds bearing those headstamps. These 311 / 18 batches is what is causing some of these very bad reviews online. The problem is the look of the box doesn't change over lot years - so you can't tell a red box 18 or 19 or 20 by just looking at the box - there are no lot numbers. You have to look at the headstamp.
From what I can gather, the recent stuff from Cabela's has all been 311 / 20, BUT several years ago they carried the 311 / 18. The problem is people who saw red/white box with "noncorrosive" got burned with mixed corrosive rounds and some swore off Norinco ever since - the see the same picture of the same box they bought and they will go ape-poo. It is understandable but I (and likely many others here) can attest, 311 19 and 311 20 red box is good to go. For me, this is based on shooting it through my SKSes, all of which are collector's grade. Still, I check the gas tube, piston rod, chamber, barrel, etc. every once in a while just out of habit.
Any other years / colour boxes (yellow, silver), I have no idea since I haven't shot them yet.