I stayed at Giorgos' place 6 nights. It is auto-check in, which is convenient if you arrive late, but very impersonal as you never meet the host of the 3 co-hosts. To check out I left the key on the table.
The flat is well situated in a nice neighborhood, less than 10 min from the metro and ca 15 min from the Acropolis Museum.
It is not on the ground floor as described, but on the basement. I suppose that is why it doesn't get very hot, I never had to use the AC.
There is no balcony as described, but a rather big inner courtyard with lots of plants. This means that it is rather quiet as you can't hear the noise from the street. Unfortunately, there were works in the building twice, for example on the Sunday morning until 13:30 so I had to leave the place and couldn't enjoy the courtyard.
I don't know if the courtyard is private, I never saw anybody but sometimes I noticed that the ground was wet.
The flat is spacious and well decorated.
The bathroom is nice and the shower is spacious. The wifi was very good.
But a few things could be improved: add a shelf for toiletries in the bathroom, leave space in the closet for the clothes which can't be hung (there were some iron items which prevented that).
To get hot water you have to press a button on the electrical board, but one time isn't enough, you have to do it 2 or 3 times.
The kitchen is ok except for a few things: the tap doesn't fit the sink, so you splash water on the floor every time you use it. There is a coffee machine but no electric kettle, and the stove was terribly slow: it took 10-12 min to heat a little water for a cup of tea. That was really annoying.
So I would say this is a nice place, which could be perfect with some improvements!