We had a wonderful stay at Martine et Raffaeles apartment. The location is very central close to the central station. The view from the roof top terace is just breathtaking. Martine was really fast in answering to our messages as we had some small problems. The elevator was broken all week so you should be good by foot to get to the fifth floor, but it is worth it!
I would definetly recommend staying here if you are in Naples.