I rarely give 5/5s but it was earned here.
It's very easy to get to the flat, especially if you allow the hosts to arrange an airport transfer for you. It's maybe 5-8 Euros more than a cab would be, but the driver (Spiros in my case) was friendly and offered some helpful tips about things to do and see.
Getting into the building and flat is very straight forward. Both the building and apartment doors use keypads, the codes for which we provided in advance of my trip. Note, however, that the door to the flat occasionally seems completely closed (and latched) when it's not. Guests are advised to give the door a little push or pull to be sure that it is latched.
The flat is new - it seems that the building was recently renovated. The furniture is simple but nice. The beds are comfortable. There's a gym in the basement and free laundry facilities. The building is fairly quiet.
The supplies were minimal (soap, toilet paper, etc). Guests can stock-up on some simple items at a small store that is ~2 minute walk away.
There are a number of nice restaurants within a 10 minute walk.
I was a little surprised by the sign in the washrooms advising guests not to put paper in the toilet. It turns out that they actually mean don't put toilet paper into the toilet! It seems that the sewage plumbing in Greece uses piping that only 2 inches in diameter, whereas its at least twice as large in most other urban areas. This was weird for me, but when in Greece...
The apartment is very well located for those who are interested in visiting some of the historic sites in Athens. The Acropolis is only a 20 minute walk away, and many key sites are even closer. The older part of Athens, Plaka, is quite nice. People who have mobility issues should be aware that it's an uphill walk to the tourist parts of the city.
I didn't spot recycling bins in the apartment.
Over all, I enjoyed my stay and would definitely go back.