In my eyes, the biggest difference Romy/Yugo is the Yugo's barrel/chamber isn't chrome lined, the Romy's is. Your call whether that's important to you, but note that either one may well have been used w/ corrosive ammo. I get a sense from browsing AK boards and vendor sites that folks think the Yugos are somehow tougher or better built overall, but I'm not sure why.

AK's are fun though so enjoy!