This was my favorite Airbnb experience of all time. If you're at all on the fence - I would recommend booking. For some specifics:
1) Giannis is an incredible host. He is deeply knowledgeable about Athens and Greece in general - providing insight about places of interest, archeology, history, art, and literature. Communication was easy, thorough, and prompt.
2) Location - convenient and safe. There are 2 metro stations within a 10 minute walk. The house is near two schools and the neighborhood felt very safe to walk - both at night and early in the morning. There's also several excellent restaurants within easy walking distance. A 6 minute walk takes you up to a panoramic view of the Acropolis and Lytebaccus. The historical sites (Acropolis, Ancient Agora, Kerameikos) are also within a 10 minute walk.
3) The space - the room is quiet and comfortable. The shared spaces are also available to use - including a nice sitting room and outdoor space. The house is tastefully decorated.
I cannot more highly recommend Giannis' place - this is what Airbnb was made for.