I stayed in Andrea's flat 10 days and I enjoyed it a lot. The communication was perfect: I rented the flat only one day before my arrival. and Andreas answered very soon. Similarly, he answered immediatly when I lost the key of his flat and I could have a new one almost immediatly without extra cost.
The main advantage of the flat is its location in Plaka, Athen's hypercenter. I would recommend anyone to go the building's roof top to enjoy the beautiful view on the Acropolis. The apartement is also very quite both during the day and the night. The only drawback that I would mention is that the apartement is very dark: there is only one small window which gives a view on a dark and empty space. The apartment is located in the groundfloor, but you feel like in a basement. I was travelling alone and I would say that the flat is ideal for a single traveler and would be correct for two people. I wouldn't bring more than 2 people, at least for long stay.
To conclude, I would certainly recommend Andrea's place. During my stay, I could benefit from a very good quality-price ratio.