The hosts are great. They response fast, waited at us when the check in time passed way over midnight, helping arrainging transport etc.
The apartment is huge, 2 bed rooms (1 with twin beds and 1 with a double bed), 1 office room with a fold out bed and 1 living room with a fold out bed. We were only 4 persons and had a room each. I guess they can arrange more beds if you need.
2 bathrooms and a kitchen with all you need (coffeemaker, oven, hub, dish washer etc). Best of all the terrasse. Its big and with a view over the city. There is retractable awnings to make shade when the sun is shinning.
The area Vomero is up a hill from the downtown area. You can take the funicalars or metro up and down. And they are a short walk from the apartment. Plenty of restaurants, cafees, fastfood etc in Vomero. Supermarket nearby.
All in all its a great base for your Napoli stay. I hope to be back in the future, still so much to see in and around Napoli.