We've had a great stay in Marco's "Maiorani Red" and Marco was an absolutely perfect host! He is super friendly, interested, honest and professional. He picked us up at the airport and when he wasn't able to drive us to the airport at the end of our stay because of work, he made sure to arrange a taxi for us.
Our stay was a little longer than most in Napoli, since we spent 12 days there. The location of the appartment smack in the middle of Centro Storico (The Historical Center) is perfect on a day to day basis, since you have super market, post office, restaurants and kiosks in walking distance from home.
The appartment is excactly as depicted here on Airbnb, the kitchen is functional, the AC is great when it's 35 degrees outside, the bed is soft and the well equipped wardrobe really made us feel at home away from home.
If you're a light sleeper or if you want to sleep in some days, it might be a good idea to bring some earplugs as there are scooters buzzing by, mostly during the day, but it does happen at night as well.

If you're into pizza (and really, who isn't?) there are several fantastic pizzarias on Via Dei Tribunali, right at the upper end of the street. I can personally recommend I Decumani on V. Tribunali 58, especially the "Decumani"-pizza is something else!

For bars and the likes, go to the end of V. Tribunali that's near Piazza Dante, there's a cute square where local youngsters and university students go at night and some great bars as well.