We spent 3 days in Giovanna’s apartment and we had a very pleasant time there. The apartment is clean, well equipped, modern, comfortable for 3 people. On the first evening the flat was quite cold, we sent a message to Giovanna whether they could take some more blankets and they immediately came and brought extra blankets and showed us how to settle the thermostat. :)
It is located in the center, however around 10-15 minutes from metro station or the central station. But if you like a little bit walking you can discover the city on foot and breathing Napoli's air.
During the evenings you can hear the party from outside (even on weekdays), therefore earplugs are highly suggested to take.
Overall experience is really positive, we would definitely recommend this apartment to stay.