Location: Penny's place is very centrally located. We were only in Athens for 2 days before going to Santorini and we got to see the Acropolis and go on a tour in the area. Many Acropolis related events start from the Museum which is a 10 minute leisurely walk from Penny's place. The great thing about the location is that it is in a semi-quiet area while still being very close to everything.
Noise: I'm a light sleeper and Penny's location and the unit renovations made it so I got a quiet rest. Once you're down the street about 200m there is more noise so the location is really perfect.
Look/Amenities: This unit was renovated recently, everything is basically brand new. Shower, AC, internet all worked great. Place also looks great with a cute balcony. There was even coffee / sugar/ fruits /eggs / biscuits for us to have even though we only used the coffee.
Host: We were greeted by both Penny & her father. They helped us into the place and I stayed in touch with Penny through the stay. She suggested a fantastic restaurant nearby (Balcony) and helped arrange the taxi/transfer back to the airport which arrived on time.
TL;DR: 5 stars without hesitation because the location, noise, look, amenities, host were all excellent.