Yiorgos is an amazing host, he provided great recommations for food and everything related with tourism. He kept constant communication and was always ready to help. He could pick you up from the airport for an extra charge (cheaper than traxis).
Yiorgos's apartment is small but it has everything you need for 1-2pax. It's not right in the city center where the mayority of the sights are, but you could take an inexpensive taxi and get there in around 10min or reach by walking 20-25min.
I'd definitely recommend Yiorgos apartment for a nice stay in Athens!