I'm a bit of an SKS collector and have an example or two of just about every variant. The worst one of the bunch is the fairly rare Albanian BTW. The Norincos are very cheaply made and it's obvious that the Chinese took shortcuts. Aside from the Albanians, every other model seems better made than commercial Norincos. However, my Norincos do shoot well and have been 100% reliable.
(BTW, I have a real Russian Tula SKS with a canted front sight, go figure).
The Yugos are very well made. The problem is, many were not well maintained. If you find one in good condition, it is very reliable and accurate. Yugo SKS (and AKs) don't have chrome lined bores BTW, so look for pitting. I remember when the Yugo 59/66s were all over and cheap. Many folks bought the $100 specials instead of spending another $50-100 for a mint "unissued". The cheaper, worn out and poorly maintained guns had problems with the gas valves and wouldn't cycle reliably. Usually replacing the valve fixed the problem. I have one 59/66 that has maybe 100 rounds through it. I have the original log book for this rifle. It is very nicely made and shoots exceptionally well.
I have never seen a Yugo with canted sights. I have seen Norincos with such manufacturing defects. Yugos don't have pressed and pinned barrels either. The machine work on a Yugo is very nice when compared to a Norinco.
You can't just generalize and say all Yugos are crap. It just isn't so. Poorly maintained rifles will have a higher chance of problems. You can't say all Norincos are crap either. Some shoot and work very well, even if they aren't pretty.
My favorite SKS is the nicer of my two Romanians. It's just like my Tula actually, except its sights are straight.