We really liked staying at Aliki's place!
The room met all our needs: very clean, spacious, good bathroom and kitchen and a large balcony with a great view ofthe city. Also, I totally agree with other positive comments about the hosts. Aliki responded very quickly and friendly and Yianni gave us a warm welcome when we arrived.
We also loved staying in Kolonaki. It's a beatiful neighbourhood, which felt very safe and had lots of nice bars and restaurants. It's also very close to everything you want to visit in Athens.
There is just one thing to bear in mind: the apartment is halfway up Lycabettus hill. For us this wasn't a problem, but I could imagine it would be hard for older or disabled persons to make the climb every day. But on the other hand, you could take a taxi (which is very cheap).