The apartment is as it seems - beautiful, well designed and comfortable. There are in fact 3 balconies, and it's perfectly located in a quiet neighborhood, just a few minutes walk to the city centre.
The hosts were super flexible and accomodating as our arrival time changes on short notice. They tokk time to explain the neighborhood and city, and suggested some great restaurants. They also called a cab for us in the morning of our departure, which coincided with a city wide taxi strike.
This is a fantastic place, and if we're ever back in Athens, we'll be here again. Thanks!