The biggest problem with the yugo's reliability was the timing belt. Whether it be the crappy rubber Zastava used or the fact that Fiat recommended a change at 12,500mi to Yugos 60,000. Know what happens when an intake valve hits a forged piston? it shatters=end of engine. usually this would happen between 30,000mi and 50,000mi. As far as easy to work on; ever put a water pump on one?!.
I've owned 12 and will always love them.