The location of the apartment is just the best - 2 min away from Syntagma square (train from the airport gets there), 2 min away from Plaka area (historical area, plenty of restaurants and tavernas) and 10 min away from the Acropolis. However, the apartment windows are facing the street which gets pretty loud at night - there is a restaurant right in front and also noisy ACs hanging on the opposite building. Better to take some earplugs if planning to stay there.
So 5/5 for the location and apartment, but 2/5 for the noise outside.