I doubt you could find a better location. The apartment is located right in the heart of it all (Acropolis, Agora) about a 5 minute walk from Monastiraki. Given its proximity to the station, it's easy to take the train in from the airport; it's a straight shot.

The apartment was awesome. Overall, it's well furnished, has a comfortable bed, and even had all the extras you could ever need (e.g. coffee, spices). The shower is great, and the terrace is specifically wonderful. Francis was incredibly hospitable, and he and his staff communicated really well. Next time I'm in Athens, I certainly will stay with Francis again!