Overall our time at Nestor's was fine. There is one thing I would like to mention, that seems very important - if you are coming from a country that is culturally and geographically different from Greece - make your own research about the neighborhood and Athens overall before coming here. The location of the apartment will look very...I'll say unusual, but it is fine, it is safe and very close to everything!
Another note, if you are allergic or sensitive person, get some Benadryl with you, you'll need it.