I had a great stay at Attila at Kleio's place, with one minor hiccup (see below). The location is great and within walking distance to a lot of sights downtown as well as the metro. The apartment itself is lovely, spotlessly clean, and well appointed with everything you might need during your stay. There is a grocery store next door as well (which was incredibly convenient). I loved their apartment.
This was one of the best AirBnb stays I've had, however there was one miscommunication issue at the end of my stay that is important to mention. I was offered airport transportation for forty euros and originally accepted because I had a very early flight out of Athens. I then found my own free transportation the day before my flight and texted to cancel. I was told that it was "too late." It was short notice, but I said I had my own ride to the airport. Unfortunately, I was never given any contact information for the driver (I have no idea if this was a taxi company or what) so I couldn't even call myself to cancel. The ride was not cancelled, and I had to explain to the driver personally the next morning that I had tried to cancel the car because I no longer needed a ride (he was understanding but said he wasn't told). Needless to say, I did not accept the ride to the airport, but I was later charged forty additional euros for airport transportation. I had to contact AirBnb support several times. My advice would be to either not accept transportation at all, or at least ask questions and be sure that you can cancel the ride if needed.