Great location, close to Kerameikos metro station (where you find the airport metro). The host was very helpful, kind, and replied quickly during my stay. The bathroom was good and had a washing machine, which is great if you want to stay in Athens for more than a week.
It did get a bit noisy on a few occasions: There is a Tuesday market in the street outside, where they set up the booths very early. You will also hear the neighbours (and their pet) quite well. The apartment is not very well stocked - I would expect there to be coffee available for every day, but there wasn't. The kitchen could have been better equipped. The bathroom did not have any place to hang the shower head, so you had to hold it all the time while showering.
I would definitely recommend this place though. The apartment felt spacious, its location can hardly be surpassed, it has an excellent balcony, and like I said, the host was great! As a woman travelling on her own, I also felt reasonably safe walking alone before midnight.