It is a unique place, different to any other accomodations. The beds are comfortable and it has anything you may need from a flat, plus the location is perfect.
A very funny thing is that you have to go through a bar to get to the flat. The Drunk Sinatra is a cool bar to have a beer when you are about to get home, but the music can be quite annoying, since you can hear it till pretty late at night.
If I went back to Athens I would definitely repeat, but I wouldn't recommend it for families with children because of the noise.