We stayed at Orestis' place (Praxitelous 37) at the end of July - some of the hottest months in Athens. Orestis was sick when we arrived, so his friend was promptly there waiting for arrival to check us in. The place was clean, had A/C (thankfully), and we felt really safe. The apartment is also located in the heart of Athens, with an Acropolis view, and surrouding with many cafes and restaurants ! We walked to all the major siteseeing attractions - including a nightclub on the west end of town. Nothing was more than 30 min walk away.
Orestis place also had a washing machine - which was convenient given the heat and sweaty clothes at the end of each day.
We highly recommend Orestis' place when you come visit Athens.