I don't have a Yugo SKS, but over the years, I've had a couple of Russian, and more than a couple of Chinese made SKS's. Never had a problem with any of them.
If the Yugoslavs, used the machinery that the Russians originally gave them, I don't foresee any issues. I know the Yugoslavs, made changes to the design (thus the Yugo variant), but I don't believe the designs changes would cause reliability problems. After all it was a combat rifle. Just makes sure the rifle is properly cleaned once in a while, remember you'll most likely be using either Russian or Chinese ammo, and their ammo is known to be dirty.
I did read somewhere that the Yugo has a gas port that can be locked closed for firing rifle grenades. Just make sure it stays open, when firing regular ammo.