I booked Velislav for a day to show me around Plovdiv: I asked for some (but not too much!) history, a local restaurant, the main sights and a few secrets.  And we did all that, at a good pace.  Velislav's English was excellent, and he was friendly and good company and professional.  He wasn't the lowest price I got offered via TourHQ, but I'm very glad I chose him.