I would recommend staying in this flat. It's in an amazing location, close to bars and resteraunts (including lots of rooftops). The flat is located in a very central part of Athens, making it easy to just go out and explore. We recieved great service from the owner, and the flat was clean and nicely organized. There is one downside which is the noise from the street.
We arrived late at the flat and Stelios met us downstairs to greet us. He showed us to the flat, gave us the keys and was extremely helpful with arranging us a ride back to the airport at the end of our stay (again, late at night).
We were 3 guests, so having one bathroom worked out fine. The flat is designed nicely and all has a full kitchen. It has shades on the windows.