My wife and I stayed at Calliope's place for one month in September 2021 (in homeworking mode) and it was fantastic!
The flat is wonderful, comfortable, functional, and stylish. Super clean, you really get what you see in the images! The location is perfect: the metro station is right around the corner (direct line to the airport), just a 5-minute walk from Kolonaki and 15 from the city center. It's in a strategical position to discover the city's major attractions and off-the-beaten-path places.
The balcony is great - big, spacious, facing a tiny quiet street, perfect for eating and working, it is literally one added room. Overall the flat is very well lit by sunlight at any time of the day and, above all, it's very silent - a total must-have in such a chaotic city like Athens. :)
The bedroom is big, comfy, and very quiet. One day we had a problem with the bed and Calliope and her husband Dominic solved it in just a few hours! Our experience with them has been just great! They are wonderful people who provide great service - kudos!
The kitchen is big and perfectly equipped for cooking any sort of day-to-day meal. The bathroom is tiny but perfectly functional.
What more to say: we really loved our month in Athens and this flat was definitely a big part of the charming experience we had. So, if you're looking for both a cool and functional place to stay in Athens, this is definitely it! ;-)