The studio is clean, cosy and close to the Acropole and the historical center. The air conditionning made our stay really comfortable, despite the heatwave. We didn't have a chance to meet Rio but we were welcomed by one of his friend who gave us good recommendations about the area.
There is one really busy road next to the appartment, so if you are a light sleeper it could be a problem. Nevertheless, I would higly suggest you stay at Rio's if you visit Athens!