My stay at this unit was convenient and comfortable overall. Check in and check out were straightforward and easy and the location was good for getting to nearby attractions.
In no particular order, these are my observations:
The building looks a bit rough from the outside, but the apartment itself is as pictured. It was comfortable, clean and had AC and internet access.
The balcony is not the one pictured and is definitely smaller, but it's comfortable to sit out on and you actually get a better view of Mt. Vesuvius and the Gulf of Naples.
There's a grocery store (Conad City) right next door, and a refrigerator in the unit, which was very handy.
It is very conveniently located a short walk from the Duomo metro stop; however, if you use Google Maps to navigate you may get a bit turned around trying to find the building as the address pin shows up on the building across the street.
In terms of safety, I felt safe overall but it is worth noting that the area does feel a little deserted at night and the building has a bit of an overhang which creates shelter from the elements so there were quite a few homeless people sleeping by the entrance of the building at night. They didn't bother us but we were a little uncomfortable while trying to unlock the building door that night. (This was around 11:30 pm and they weren't there in the daytime.)
Overall I enjoyed my stay and would be happy to re-book if I returned.