We stayed here for one night between the two flights. The place is very conveniently located, just a 5-minute walk from Syntagma metro station. This allowed us to use the metro from and to the airport.
The check-in was easy, the apartment looks very nice and modern. Everything works great: TV, internet, shower, kitchen appliances.
It is very close to many tourists attractions - National Garden, Syntagma square, Acropolis, all the gift shops and restaurants of Plaka and Monastiraki are within walking distance.