Stefan's place is located right next to the Attiki metro station (the exit's literally on the same street, a 2 minute walk) meaning you have easy access to all of Athens and since Attiki station itself is fairly close to Syntagma/Acropolis it's fine to stay there even if you mean to hang out at the strictly downtown areas.
The place was as clean as in the photos and it had all the necessities when I arrived, with some nice added touches to help me get around. The rest of the building seems to be populated mainly by natives and has a friendly feel to it.
The host organized a taxi for me during arrival so as to make it more easy to arrive at the place and the driver himself was also very helpful in giving out some tips and getting to know the place, as well as helping with the check-in.