Salvatore is an amazing host! You will have an instant friend in him, and he will work hard to take care of you. We were excited to have him take us on a tour to Pompeii and the Amalfi coast, but at the last minute he was unable and so apologetic. He went out of his way to try to make it up to us, and was continually checking to make sure we were okay. He is such a warm, generous person.
The flat itself is as described and nicely clean. The fold out bed is small, so unfortunately one of us had to sleep on the floor - the flat sleeps 3 fine. It is also very warm without A/C, only one fan and little air flow from outside.
Naples itself turned out to be a little too "authentic" for us, but if you go, you are in great hands with Salvatore!