Our stay at Roberto's flat was great ! We had a really good time in Naples. We just had a pretty big arrestation near our place one night, we didn't felt really safe for a moment but the police is here practically everyday in the neighbourhood (usually down the front door), the shower was tricky we spent a lot of time trying to figure out how to balance the cold and the hot, and one night we saw a coakroach in the bathroom... But that's because of the outside, the flat was really clean despite of that. They cleaned all the flat before our arriving and Roberto has been really nice and helpfull !
I recommand that appartment, we enjoyed our stay a lot !
PS : go try the Colcettina's pizerria down the street, it is delicious !