The place is marvelous, i woud say a rare find. The location is perfect, I would say one of the best locations you can get. It's close to the underground, in the end of the street there is a great bakery (Το Κουλούρι του Ψυρρή) with delicious stuff. My wife and I had breakfast there very day of our stay and I wish we had this bakery at out home.
The place itself is very cozy and spacious, fully stocked and has everything you need to live in. It's also possible to access the rooftop which has a great view at the city and the main sights. If you are into the photography be sure to grab a tripod to shoot timelapse or make nice night pics.
Kostas is a great and helpful host, everything was smooth.