The location for the appartment is perfect, withing walking distance of everything we wanted and well placed for drinks and food on an evening.
The apartment itself is nice, possibly needs a little love as it is a bit worn.
The check in was quite stressful, if you are meeting at a specific time give yourself loads of time. There was a long queue at the metro when we arrived at the train station as the ticket machines were out of order, so we were late to meet our host and she had messaged saying she was going back to work. This caused quite a lot of stress as we literally had to run to meet her as we had no idea how else we would get into the appartment. The host was helpful when we asked for stuff but it was things I would expect in the apartment in the beginning (eg a towel for washing pots and extra toilet paper)
The stairs to the mezzanine are incredibly steep so I would only recommend for guests with good mobility.
Overall we had a great time in Naples.