Our stay in Athens could not have been better! The apartment was indeed in the heart of the city, everything we wanted to visit was within walking distance -- we only took the metro when commuting from/to the airport! The apartment was very clean, tidy, and comfortable; everything that we needed during our stay was there! The host was also very friendly and responsive, he answered all our questions and was always happy to help with whatever we needed.
If we come back to Athens, we would love to come back to this apartment if available. Ευχαριστώ πάρα πολύ!!
P.S.: If you want to grab some food early in the morning because you have an early ticket to visit Acropolis or other key monuments, we highly recommend you go to Picky, a great vegan- and vegetarian-friendly place that opens early enough for you to have an early morning (it is ~5min from the apartment). There is also a great tattoo/piercing place, Luv N Roll, just ~2min walk from the apartment, highly recommend as they have wonderful artists!