Christos met us (although we were a bit late) and communication was excellent. Flat is very close to metro station and bus station (for bus to Rafina port - less than 5 mins walk) and therefore easy to get anywhere - airport or tourist sights. The flat is on a pretty side street without traffic. Balcony large and good for eating breakfast or dinner. All very comfortable. All rooms have independent air con, beds comfortable, bathrooms good and everything clean. We stayed in August so air con a must for sleeping but eating on balcony in evening was very pleasant.
We walked to central Athens - Acropolis/Plaka area in about half an hour, but can get there in a few minutes by metro. Area around flat felt safe with two supermarkets, lots of cafes and an excellent patisserie (a few shops towards metro from small supermarket). Archaeological museum moments away and worth a visit.
We loved Athens and Christos's flat was a perfect place to stay. Would definitely recommend and stay there again.