So much to say about this place! We stayed for a month so have a lot of experience. First (and most important) the good.
The apartment is lovely. Eclectically decorated with lots of interesting books, backgammon, and pieces of art. There is two heatpumps / aircons and a nice heater that we can sit in front of (we were there in winter of course!).
The balcony is AMAZING. Huge, well furnished and thick with plants we spent a lot of time out there and would have never left if it was summer! There is a school directly below the balcony, and I thought it was going to be a problem, but it really wasn't. They don't start until 9am so we weren't woken, and they finish around 3pm. It is noisy, but it is a happy noise you quickly become used to and it just becomes a positive background feeling.
Close to supermarkets and Wednesday vegetable market is AMAZING. Short walk and shorter metro elsewhere in the city.
The bed was extremely comfortable and a highlight of 3 months in other airbnb's. Everything is a good size (lounge, bedroom, kitchen). Quiet at night time. In terms of value for money we really felt we got a great deal, and were happy to have stayed there.
But there are drawbacks. The neighbourhood is really the core of it. We knew Athens had poverty and troubles, and that the neighbourhood was some of the worst of it. We had even read in different reviews of this airbnb that it was bad, but still I honestly wasn't prepared for the extent of addiction on the streets. There is homelessness and people openly injecting drugs on our street and the streets surrounding and it can take you aback and make you feel uncomfortable. On close by streets there seem to be permanent gathering places that regularly had 10 or 20 homeless drug users gathered. The upside is that while uncomfortable we didn't really feel in danger at any point, nor were we hassled or approached. They seemed mostly content to be doing their own thing. Also, it was only 5 minutes of this kind of stuff before you emerged into more orderly suburbs.
Another drawback is that the walls of the bedroom are paper-thin and we could hear the neighbour talking, watching movies and other less innocent activities at all hours of the night and early morning so earplugs were necessary (although not always sufficient) to sleep most nights.
The washing machine hose also sends water into the shower, which is fine but leaves a kind of film on the bottom of the shower which wasn't so nice. The kitchen was also lacking any kind of knife for cutting with.
Overall, we still gave it 5 stars because we had a lovely time there still and the apartment was lovely and as was the host. There is nothing she could do about the neighbourhood or the neighbour and so it does not reflect on her. But it would be dishonest not to mention these things.