I can't comment on the balcan's dogs, as I never saw one.
But I have a small experience with the Estrela Montain dog, as I'm portuguese and my uncle always had some at his farm.
As few of you know there is 2 types of EMD the long hair the most common, and the one that has been exported, and the short hair one, much rare.
The 2 types had in the past different proposes, the long hair were use as home guardian, because of its massive aperance provoked by the hair. The short hair were use to help the shepperd on the montain, as it is ligther and more agille than its brother.
Today the EMD is most use as house guardian as there is very few shepperds on the montains, this is a very confident dog, calm at his owner presence but with a great gardian instinct on his own.
During the 70´s were normal to mix the EMD with German Shepperds, there some of the reasons there is some dogs considered pure with darker colours.
In my opinion the bests breeders of the breed still in Portugal, as it is becoming one of the most popular breeds in the country I'm affraid we will lose most of the quality.