I don't know where Dan gets his info, but the healthcare in Bulgaria is NOT free! If you're a Bulgarian citizen you pay some percentage of your salary each month to the health fund. Then when you go to see a doctor you pay a small fee, about $1.7. No donations. You may have to pay additional taxes/fees if you need to stay in a hospital and got some more expensive operation. Also buying drugs may be covered or may not by the health fund.
EU citizens got some of the healthcare covered by their country's helth fund, but I'm not much familiar about this.
If you're a foreigner you can go on paid consultations/examinations, where the first consultation fee is between $20 and $45, depending on the hospital, doctor and etc. For additional care you need to pay more.
As for the quality, there are very good doctors here, but they're mainly in big hospitals in the capital Sofia and a few big cities. Fact is that many of the small hospitals have old equipment and a lack of personnel.
Regarding the waiting - if you're going on a paid consultation usually there's no waiting when you have booked an appointment. Other times there may have some or more waiting, it depends on the case.