Pros: Great location, 5 minutes from Omonia station. Quiet at night. spacious. Clean room. A desk and a chair. Equipped kitchen. Gerhard was very nice the first day and he waited for me in the heat despite the fact that I was 15 minutes late.
Cons: The light. There´s no sunlight at all in the room, it has a small window but it faces an inner wall so it feels as if you were at the bottom of a well. In the common spaces there´s no light either. The living room and the kitchen are quite dark, so you really need to get out of the apartment to get the impression the sun has gone up. To me it felt like a cave and it is very difficult to air, because no air moves so the atmosphere felt stuffed and not fresh. I found the aircon unpredictible and difficult to use, it looks old and I could not figure out how to use it half of the time, a fan was provided anyway. The washing machine is incredible noisy and with 4 people in the house it was in use very often. When the washing machine is working the noise in the room is quite loud so if you´re planning to teach or sleep during day time it might be hard. Some of the other people of the apartment sometimes smoke.
I stayed longer than a week in this place and I would not stay again. It was so dark that I felt a bit depressed and I just didn´t feel like spending time there. I think this place might be a good option if you come to Athens for sightseeing and you are planning to spend the day out and only sleep there (and if you´re on a short budget). If you´re planning to spend part of the day in the room I would not recommend it. I would not stay longer than 4 or five nights.