I chose Simone's place because I was on a budget and I got what I paid for.
Andrea, who manages the place, was a very pleasant host. But Simone failed to communicate with me in the day leading up to my visit, and I ended up waiting an hour for check-in after I had already arrived at the apartment. The neighborhood is close to the train station and historic center, but is sketchy in the evenings. My room was also unbearably hot; even with a fan, I did not get a full night's sleep once in the four days I was there.
If you are on a budget and visiting Napoli for a day or two, and not during the summer, this place is fine. Personally, though, I wish I had spent the extra $20-30 a night to stay somewhere else.