It's a great place to stay in Athens. We were a group of 7 people and the apartment was just perfect for us. There are 2 bathrooms, both with showers, so we didn't have to queue. The kitchen is amazingly equipped, we cooked a lot in the apartment and didn't lack anything.
The apartment building is located on a busy street and the windows don't block the noise much, so it wasn't very quiet at nights. We stayed in December, so it was a bit cold because of the windows as well, but a pair of house shoes and air conditioning set to warming mode solve this.
The communication with the host was smooth and very pleasant as well, Panos was very helpful, hospital and nice throughout out stay.