Choose this flat! It’s not too big and not too small. Loads of room on the terrasse. Big bed. And everything you can imagine you would need: first aid kit (when you need a plaster after having walked too long on the Acropolis), a kettle, coffee machine, washing machine, a clothes horse (drying rack), vacuum, air conditioning (Athens is very hot!!), very good wifi (i had no problem connecting to my digital office when needed and attending vidéoconférences) very convenient location 3 mn from Kerameikos Metro station (the line that comes and goes directly to the airport !!). Which is also 2 stations always from downtown and most historical places.
Also the hosts are very friendly. They are very responsive and let you feel welcome which is very very appreciated.