The appartment (we were in Hesperides) is modern and clean. The decoration is tasteful and the balcony is very nice.
The Kerameikos metro station in nearby (less than 10 minutes walk). Next to station and near the appartment there are bars/restaurants so you don't have to go to the more central area around Monastiraki.
The appartment has everything you need, even a dish washer and there is also a washing machine in the basement area of the building. We used the Gym (in the basement) which was good (has also airco).
A small supermarket is nearby, a bigger one is a few minutes walking distance (I recommend the bigger one).
Windows have shutters and mosquito screens,: good. You can hear some street noise though (also the green metro line which runs not far from the appartment building) , although there is little traffic at night
Communication with Esmeralde was great and access using the codes worked fine. We also liked the fact that there was an elevator as we were on the third floor !.