We absolutely loved our stay (5 nights)
Host: Very accommodative. Helped me plain my stay even before I arrived. Arranged pickup and drop-off at the airport at very reasonable prices. Received me rather late in the evening, went over all the details about the apartment and places to visit, eateries etc.
Location: Right in the middle of where you want to be. Surrounded by a wide range of food options (amazing street food to fancy restaurants), all local sites were within a mile and hence easily walkable. We didn't have to avail local transportation.
Apartment: Modern apartment. Entry is via a digital key. All amenities are very modern. Most notably, though the apartment doesn't call out heating - the apartment has both heating and cooling options. Was a blessing for a December visit.
I would stay here in a heartbeat the next time I am in Athens.