The difference with places like Poland and Hungary, as distinct from much of Bulgaria, is that you have an opportunity to buy property at local prices in a real marketplace. In the case of much of what is being marketed to foreign buyers in Bulgaria however, you are operating in an artificial market with prices in many cases a multiple of the market value (on a good day). Add the "guaranteed rental" scam and huge layers of commissions to this mix, and you are guaranteed to lose heavily when you try to exit. Nothing is surer, and anyone who can't see this is either in denial or has a vested interest in selling to foreigners. There is simply no middle ground in this scenario, no possibility of a "maybe it will work for me" situation.
If you go to Krakow or Budapest and buy what the local market demands, i.e. buy good property that is also being bought by local buyers, and you buy it at or below the going rate, then you have an asset that is at least worth what you paid for it. On the other hand, if you buy at three or four times the going rate, in a market with no resale demand and a huge oversupply, you are flying in the face of all market wisdom.
The difference between investors and people who buy the products on general sale in Bulgaria is this: Investors do the math, do the research, and try to get value for their money; buyers of this stuff act on a hunch, are easily swayed by salesmen and women, and make spurious comparisons to the price of houses back home. Guess which ones will come out the other end with their funds intact?