Slovenia was the richest federal unit within Yugloslavia and I guess that makes them the most successful experiment in socialism like ever. I think at that time they were doing better than the current Greece and Portugal. However, the rest of Yugloslavia wasn't that great.
It was very regional in Yugoslavia. For example, eastern Slovenia was behind Zagreb and some coastal areas of Croatia. It was behind cities like Novi Sad, Belgrade in Serbia and many others. Slovenia as a whole was of course better developed partly due to commerce/proximity with Italy and Austria.
Sarajevo in the 80s was pretty good and it was still behind Zagreb and Belgrade. I moved to northern Italy in 92 and the standard of living wasn't that much better for most people compared to a larger Yugoslavian city in the 80s.
