Location - it is located in a very hipster area with a ton of cool restaurants, bars and cafes literally a block away which was so convenient after a long day of sightseeing in Athens. 5 minute walk from Monastiraki and can easily walk to the major attractions in Athens (Agora, Tower of the Winds, Acropolis, Plaka, etc.).
Space - exactly as pictured and even a bit more spacious than I anticipated. It also has a small elevator which makes it easier to get your luggage to the flat.
I highly recommend Yiannis' place to anyone going to Athens. I will definitely stay there again when I am back in Athens.