Panos's flat was a great place to stay in : a querky, well furbished, and well located place with close amenities and a very nice rooftop.
10 min walk from Kerameikos station, 3 min walk from Monastikari (flea market) - nice coffee places and supermarket across the street.
Small downside - size of the bed and a bit noisy at night.
Otherwise, Panos is a great host. He had prepared maps and tips to point us to key highlights/local greeks taverns and museums - very helpful when you dont know Athens.
He was also very accomodative and allowed us to leave our luggages in the flat after the check-out time.
We would definitely recommend this place for a stay in Athens!