Great location, it's close to everything, and, most importantly, it has A/C.
The apartment itself is nice and well stocked. The air conditioner in the living room worked okay, but the one in the bedroom was perfect (we wouldn't have been able to sleep at all if it weren't for that). The bed was sizable and comfortable. My girlfriend appreciated that they didn't use strongly scented detergent on the sheets (she often has allergy problems). The kitchen was well stocked, with all kinds of things for cooking. The host had a few extras in the fridge, too, like eggs, yogurt, etc. There was also a large bottle of water in the fridge, which was highly appreciated when we arrived because it was blazing hot in Naples. For our own food shopping, there were multiple grocery stores nearby (I'd recommend the Sole 365 just a few blocks away). There were also plenty of restaurants and bar options around.
The only cons are the elevator is paid as long as the building attendant is there (which, to be fair, is clearly mentioned on the listing); if your phone is 4+ years old, there's a chance you won't be able to connect to the Wi-Fi because the network is using a newer form of security (which most hosts don't use because it excludes some devices, but we were told couldn't be changed); and most of the outlets in the apartment won't fit anything with a large plug (like laptop chargers).
We were very happy with our stay and can't wait to see Naples again.