Me and my girlfriend, we stayed in this apartment for a few days and would recommend it to everybody who wants to see Athens and stay on nice place directly in the city.
Apartment is nice furnished and very clean. You have everything there what you need including small kitchen and air-conditioning. It is located directly in the centre of the city with just a little walking distance from the best monuments of Athens. Location next to metro station gives you very good connection to the Airport and the rest of the Athens (and the see).
Nikos was very helpful, we arrived very late in the night - he was waiting to greet us and available on phone for our questions. Our flight from Athens was later in the afternoon and there was no hurry with check-out so we could leave out stuff there. It really helped, as we did not have to walk around the city with our backpacks.