There is absolutely nothing to complain about.
Nikos is a great host and a very kind person. He even left snacks for the group, took his time to explain everything, made great suggestions for our stay in athens and was always available.
The apartment itself is really beautiful and looks way better in reality compared to the pictures. It is really huge and there is enough space for everyone.
The apartment has a good location. There are bars and restaurants nearby.
I have nothing else to say than that it was a really great experience and I would always come back when I will be in Athens again.