The apartment and hosts are great. Apartment is easy to get by any mean of transportation: bus stop right in front of the door, metro station - around the corner (literally!), taxis find it easily. Inside it is clean and cosy, with separate rooms with locks, and even balcony (though I did not use balcony, as it is above busy street and car gases smell bad). Also nice touch - good windows that do not let sounds inside, as street is busy and noisy, but as you close the window - it's as if world outside does not exist)
Hosts are really nice and welcoming: it was raining when I came to Athens (through all my stay), and it caught me unprepared - they let me umbrella, which I was using until bough my own.
Finally, it is located in walking distance from Acropoli and other historical sites. And it has pretty much everything right on the first floor of the building: pharmacy, cafes, sweet shops.
I'd definitely stay there next time I'm in Athens)