We would definitely stay again!
This apartment is in a really great district of Athens with cafes, bars and restaurants nearby all with a locals vibe. It is a 25 minute walk or a short (very cheap!) taxi ride into central Athens.
We (5 of us) found the space to be very good. There was some pool, some sitting on the balcony with genuinely great views etc. which meant we did get to enjoy the flat as well as the city.
Our stay was in October but the air con was all present and correct. The lift is a little temperamental and perhaps do not use if there are more than two or maybe three of you (flat is on 5th floor).
The positives massively outweigh and negatives to this property and it comes highly recommended!