From my experience the planes were basic, a little chilly in some places, slightly rickety on landing and take off but flew exactly on time. No big prolems.
I don't know if this is different from 2-3 years ago though
Very rickety - no alchol served on board! Meal ham and lettuce (take a sandwich) ohh and either a snicker or Mars bar!! Also start worrying if you get transfered to Bourgas - No rep to meet you , wait for 3 hours for a coach then a 7.5 hour coach ride - on the coldest coach on earth - Don't mean to worry you or anything.