Upon arrival, we were welcomed by a friend of Anna & Efi. She explained everything well. Also, Anna & Efi prepared a wonderful little guide which was very useful during our stay.
The apartment is extremely well located, within walking distance of all major attractions in Athens center. Although the apartment itself is in a quiet street, the area is lively with restaurants and bars just around the corner.
The apartment is just as described: it's cosy and comfortable and we liked the overall design and functionality.
We didn't use the terrace because of the summer heat but I imagine it being nice when it's not so hot.
I would definitely recommend staying at Anna & Efi's place.