Hostel Mancini is in a great location, by the Napoli Centrale train station and near Corso Umberto 1, a main road. They provide a map and pizza (delicious!) suggestions. Breakfast is good, good variety. The TV room has couches, the place is comfortable and clean!
FYI, the wifi doesn't work in the bedrooms, only in the main rooms.
My only complaint is they had us switch rooms after the first night of our stay. I don't know why, since other girls from that first room stayed and only we switched. We were changed to a room with men, so I suggest requesting a same-sex room of that's a concern.