* 10% income tax (second lowest in EU), 5% dividend tax
* Very low costs of living (rent is 300-400 eur for a flat in Sofia)
* Relatively easy to start companies
* It's quite safe, at least safer than Naples from where I am from
* Very good quality of food
* Close to the seaside (about 3 hours from Greek coast also)
* Nice summers and autumns
* A lot of mountains and land around Sofia, nice nature around
* !Important: probably lots of EU funds for startup. You can probably get funds for your startup w/o investors if you win a EU project
Personally the only issues I have seen are:
* Yeah, lots of people have left, many are in the process of leaving
* "Made in Bulgaria" is not considered a very good brand in EU like "Made in Italy" or "Made in Germany"
Edit. Added EU funds bullet.