I've never met hosts like Anna and her husband Petros.
You can truly feel that they don't do it for the money, rather they REALLY like to host people.
They helped me with anything you can imagine - from tips and detailed travel plan, through laundry and even cooking some delicious traditional Greek food so I can try it (More than once!).
The apartment is very cozy. It's got everything you need, including the little "touches" that make it feels homey.
The WIFI is ok and similar to all other places I've seen in Athens, and the balcony is a huge bonus.
It is a bit more far from the city center, however, there's a good metro not too far from the apartment that can get you there pretty easily. In addition, if you like walking, it's still in a walking distance.
All in all I had a superb time there and I will definitely come there again.