First things first, the apartment is really nice. It is equipment with almost everything you can wish for. It is clean, the neighbours are polite and the doorman or the doormans are friendly.
The neighbourhood is quiet almost all day around, although you are not that far away from the Piazza del Plebiscito.
Stores like grocery stores and other daily useful stores are within walking distance. There is (maybe) some difficulty to carry the groceries to the apartment, because you have to walk up a somewhat steep road. So keep that in mind.
You can discover a great part of the city by foot or with a public transportation of your choice. A great variety of cultural sites like the PAN and others are really close by. Then there is the Via Partenope with its restaurant and bars.
Guglielmo and his co-host Simonetta are in my experience really great. Communication with them is flawless, they are helpful and really kind.
So the Overall experience was great and I can honestly recommend this apartment.