Positive:
The apartment is perfectly clean and functional, so is the whole house. The rooftop is really amazing! We had breakfast there every day. Kitchen is fully equipped and working, hot shower is no problem if you follow the instructions, the shower is huge and comfortable!
The location is 3 min walk to Monastiraki station and very close to everything, we walked everywhere (apart from the beach and Piräus) - any sight is within maximum 25 min walk and through lively neighbourhood full of bars, cafés, little shops and restaurants. Psyri is a quarter where not only tourists but also many greek, mostly young people go out for food and drinks, many expats, internationals (students?), graffiti at the walls...You can find good prices in restaurants, it's not the most touristy place like in Plaka around Acient Agora or Akropolis.
We always felt very safe even late at night walking around the neighbourhood.
The staff (we met a guy and a young woman) is super friendly and most times there was someone in the office. Check-in was easy and well prepared with a lockbox, so it doesn't matter what time you check in, in case you should arrive late at night.
Netflix is working on the TV! Also, we could connect our phone to it and watch other films from other streaming platforms.
Two negative points:
It's extremely loud even with the windows closed, because there are several bars and restaurants just below the apartment, which is on the first floor. Even during the week on working days there was loud music with heavy bass until the early morning (3-4 am), so we could barely sleep. If you choose the place because of it's central location and also like being in a party place like that, think of bringing earplugs!
The bed is unfortunately not comfy at all because the mattress is too soft (yet harder at the edges so you would roll in the middle), we had constant lower back pain during our stay. I told the host already, maybe he'll replace it in the future!