This is a fantastic place to stay, and I thoroughly enjoyed my time in Naples.
The apartment is spacious, clean and beautifully decorated. In particular, the bedrooms have lovely furniture and decoration - which gives a really nice classic Italian feel. The terrace is also great - and the breakfasts that Valentina serves here are really good. It's a perfect way to start the day eating breakfast in the sun!
The location is really good - near enough the station (where the bus from the airport drops you off) to be convenient, but far enough to be away from the usual big city train station noise and chaos. The historical centre of the city (with great pizzerias and shops) is just a short walk away.
Valentina and Dario are great hosts - communication before my stay was great (prompt, clear, helpful). And during my stay they were very helpful in providing help and advice about the city and what to do.
So, in summary, I would highly recommend this as a place to stay!