We only had a couple of days in Athens, but loved this apartment because it was central to everything which meant we could walk everywhere and pop back for breaks if we wanted to. For arrivals/departures it is only a short walk to the metro.
We were there for a Friday and Saturday night..so there is noise from the local bars/clubs....but if you close the bedroom door you can't hear anything (except the 7.20 am church bells on Sunday morning).
Our host was great and met us outside on arrival and gave us a great rundown of local supermarkets, eating places etc
If we are ever back in Athens we would definitely want to stay here again.