Smaragda and Dimitris anticipated our stay well with useful tips; they were always very reactive - including during the airport-to-flat period -- before we arrived. They then provided us with a comprehensive tour of their lovely flat and were ALWAYS available and helpful during our stay.
Their flat is lovely: spacious, clean, with an awesome terrace and, importantly for a family, very quiet. The area they live in is perfect: calm but packed with lively cafes and restaurants; it is within walking distance -- or a short taxi ride when it gets too hot -- to the old town and Acropolis.
We would definitely love to stay with them when in Athens again.