My boyfriend and I stayed at Athina's place for 4 nights and it felt comfortable and as cozy as a weekend home could get.
Size : There was a living room, bedroom with a comfortable double bed, bathroom (both bathtub/shower), kitchen and a balcony. All room were thoughtfully decorated and were the right size for a couple. The apartment will fill a maximum of 3 adults and anything more would be a bit of a squeeze
Check in/out : Athina was there to receive us for check-in (at around 7pm) and we used a keybox located at the entrance of the building for check-out.
Location: The apartment is located is definitely withing 10' of walking distance from the Acropolis and has a number of nice pedestrian passageways and restaurants/bars close by. There is a supermarket/pharmacy located right opposite the building for any emergency needs. The building that the apartment is located in is also secure so there's no cause for concern at all.
Other: Athina had filled up the pantry with all our breakfast needs for 4 days. We had milk, bread, cereal, honey, tea, coffee, cheese and some basic condiments in case one feels like cooking. She's also super friendly and was very responsive to any requests.
It was a great stay and would highly recommend it to anyone visiting Athens!