As a Greek person who moved abroad and came back to Athens as tourist, I can only say that this house is a hidden gem. Best place you could stay in Athens center, in a walking distance from all important archeological sites, restaurants, bars/cafes, shops.
At the same time, it's located at a very quiet spot, in a pedestrian street. No cars/people passing by at night.
Overall, an excellent choice to enjoy the best Athens has to offer. Don't miss it!