Given 5 stars as overall the apartment is great value. For comparison around the corner theres a hostel where two beds in a 6 share dorm works out about 25 euro more a night for two people, rather than a couple sharing a private room here.
The apartment is on the 3rd floor (elevator in building). 7 rooms inside the apartment- it is set up like a hostel stay, with seperate lockable doors. The bedrooms are quite spacious, better than we expected. Comfortable, clean, with aircon- you cant ask for more. In the hallway near the elevator there are 2 bathroom/ showers. Our stay was uncrowded, availability of amenties was never a problem. They are cleaned well daily but individual stays on cleanliness Id say heavily depends on the hygiene and cleaniness of other guests. The toilet and shower are in the same space (1.2 metres by 1.4 metres approx)- so you are standing right next to the toilet while showering-- this was the one thing that would give us pause about staying again, but personally given the price I think it was fine for a few days- Id recommend shower shoes though.
Safety of location- welcome to Athens; there are a large number of homeless/ refugees on the street begging, there is graffiti everywhere, and you will probaly see open illicit substance use. Personally this for us does not make it automatically unsafe- over 3 days we had no issues but it did give us pause to go out late at night. The apartment is located just inside a street market, on the weekend the market was closed and a soup kitchen was set up near the market entrance so the unfortunate were congregated in the area- this may make some people uncomfortable, but not automatically unsafe. But someethin to keep in mind especially if travelling solo. For example- walking 300 metres down to Monasteraki station you will pass about 10 people begging on the footpath off to the side not bothering anyone. The accommodation IS very centrally located, Monasteraki is the heart of Athens we found, I think the further out youd go it would only be worse.
Sorry for the essay but when people commented unsafe neighbourhood I know we had concerns so hope it helps future guests.