It's a nicely relaxed and relaxing place. It offers a new slant on life (urban or rural). It's not obsessive -- "a little dab'll do you ya" is the attitude, they are never pedantic about results around here. People are quiet and appear quietly happy, even if all of them claim to be miserable or sick or on the edge of bankruptcy. Brits are respected and liked. Not speaking the language isn't really a problem -- most Bulgars make the effort for you. Okay, so you might get ripped off by the occasional waitress coz she sees your fat foreign wallet coming, but hell, it's chicken feed, so relax, don't worry, be happy (go native, in other words)...
What does it for me is -- there's no street crime and no street "attitude" to speak of -- nothing like the UK where it seems you run into self-confident and aggressive crowds of young louts at every turn, in every town or city centre and in most suburban centres. Horror stories about the Bulgar mafia abound and one perhaps ought to watch oneself a bit in Romany areas, but unless one wants to make it big in local crime, all that's of no concern.
It's cheap, though for property and basics only -- some things cost a packet, coz they are imported. And EU membership will push prices up, no doubt. So enjoy it while it lasts.
As for it's nice climate, hmmm... Loads of rain last summer. HEAVY winters!!! HEAVY summers! Nicest in spring and autumn, in my humble opinion. Repair to the UK for Crimbo and high summer hols. Generally nice, dry climate for arthritis sufferers, though.
A big minus is the bureaucracy which is heavily Continental -- demanding, slow, regarding ordinary people as supplicants, very complicated, and very intrusive. You have to cart all sorts of bits of paper around, and they are all checked regularly and fray, and you have to go get duplicates...
Another big minus is roads and road manners. Bulgars are appalling drivers (incompetent AND aggressive) and die X times more often on the road than British drivers do. So drive defensively and don't let the bastards grind you down!
Oh, and beer's nice