This is a really nice apartment, very very unusual for its size and spaciousness, right in the middle of the old historic part of Naples, about a 10-15 minute walk from the station. There are four very large bedrooms, 3 bathrooms, a large living room, and a combination dining room/kitchen, plus a laundry area. There is also a terrace, which we didn't use because of the weather plus we were only there for 2 nights. If you don't like stairs: this won't be the place for you. It is on the top floor of a building without an elevator, so if you are going to be going back-and-forth all day long, you need to be prepared for a lot of stairs.
The place is fairly modern in its decor and furnishings and served us (3 couples and a single) very well. The host was very nice, and helped us out by setting up a crib for a baby ahead of time.
This apartment would be a great base for exploring Napoli---you are right in the middle of everything---for large families or groups of 3-4 couples. There's a ton of space, and it's very comfortable with good privacy between the different bedrooms. Each bedroom is spacious; the bathrooms small but usable.
The host was available when we had a minor problem and resolved it very quickly.
If you don't mind the stairs, this is a 5-star place. If you don't like stairs: well, this is probably not for you.