The apartment building is safe and clean and would appear to consist fully of AirBnb rental flats. The immediate area of the apartment isn't the nicest but it is just a couple min walking distance from the nice restaurant and bar streets in the plaka. Also just a block to the other direction away from the acropolis there are some really nice restaurants and bars as well that are far less touristy and are just filled with locals.
The place itself was clean, but it was very small but we were fine with this as it was so affordable. So if you're looking for a simple, affordable and clean place just to sleep the nights that is very conveniently located this is a good choice.