Claudio's place was perfect for our needs. It was within easy walking distance of just about anything you need within the historic centre, and is about 25 mins walk to the main rail station. It is particularly close to the via dei Tribunali, with many famous pizzerias etc.
The apartment itself was great, with one double bedroom and one twin room (I believe both can be either double/twin as required). Having two bathrooms also made things much easier for the group.
Claudio was a great host, with quick responses throughout. He also allowed us to check in early, and leave our bags in the lobby throughout the day of our check out, which was extremely helpful.
If/when I come back to Naples, I will definitely look to return to Claudio's place.