To be honest I have not read or know anyone that has gone to Sunny Beach or Bulgaria and raved about it and said they would go back.
I agree it's appeal is that it's different and not many British, but I would prefer to be in a minority with Scandinavians or Dutch rather than Russians.
Talking...
True, I was there in May, but you could have said any Greek Island, but I am very biased as I love the Greek Islands, just have to be a bit careful that you don't go to the ' lively' resort that exists on most of the popular ones.