We enjoyed our stay at this gorgeous apartment- and think it's a great haven for two people. The lift, balcony, and completely comfortable bed, bath and living rooms all made us feel relaxed each time we returned to the apartment. For longer stays though the bed and bath rooms needed shelving of some sort. There is some noise from restaurants, but closing the windows/doors blocks that out. Speaking of which - there are really great places to eat and drink right by the apartment.
You can also walk to nearby suburbs like Kolonaki and Syntagma quite easily. Or the metro is less than ten minutes away.
We can highly recommend Nikolas's place!