We stayed two weeks in Roberto's apartment in Napoli. It was amazing! The apartment is beautiful, spacious and offers everything you need as well as a fully-equipped kitchen. Everything is very clean. The apartment is located at the top of the building and you have an amazing view from the two balconies down to the street, where you will quickly realize that you are far away from touristic hot spots, hotels, etc. and inside the heart of Napoli. Here you see real Napoli people which are all extremely friendly, such as the neighbors in the building or the people on the market just a few minutes away by foot, where you can buy amazing fresh fruits and vegetables. In addition, there are really good local restaurants just in the neighborhood which we strongly recommend because the food is amazing and it is really not expensive (e.g. Casa del Caffè).
We really had a great time in Roberto's apartment and in La Sanità. One last thing to say: The traffic in Napoli is crazy. We've been there by car and we had life-changing situations during our drives through Napoli :D But it is possible, we survived it!