We stayed for 4 days in Yorgo's apartment: the house is really nice: clean, well kept and spacious with a great kitchen. The balcony with the pool is wonderful (due to high temperatures (one day even 40 degrees!) we didn't sit outside often).
The house is not in the touristy centre of Athens but in a quiet area, so we took taxi's (4 to 5 euro per ride, we used the Taxibeat-app which was a great tip from Helena and Yorgo). When we arrived Helena gave us a very warm welcome and told us everything. So we recommend this place to everyone!