My wife and I had a one-month stay. The best part of this apartment is its location - super central, very close to Acropolis and metro station, and yet in a safe and pretty tranquil area.
The apartment itself is nice and cosy, Airbnb photos are accurate. Good wi-fi. Easy check-in and check-out. Great bakery nearby, lots of cafes and restaurants, several supermarkets just 10-15 minutes by foot.
If you're going to spend several days in Athens - don't think twice!
If you're planning a longer stay, you should consider that apt is located right above the bike-tour office. There were a lot of tourists every day during the working hours, talking and laughing. And one of the guides is a smoker, and he smokes next to the office (and apt windows). So, working in a room with open windows wasn't very comfortable. And closed windows made the apartment both stuffy and chilly, cause there's not so much light on the ground floor.
The kitchen could use some attention from the host. And having clothes drying rack would be nice.
All in all, we had a good stay. But this place often motivated us to go outside for a walk :)