We had a great time and we would choose the apartment at any time if we had the opportunity. The place is convenient in every way, and offers all that we expected and all you need - a very pleasant atmosphere, good beds, in the centre and close to the station.
The best is the terrace. Surprisingly quiet (on the inside of the block), overlooking the city and Vesuvius.
Klaus is a great host, and was very flexible when we had to keep rescheduling the arrival time due to all kinds of unfortunate hick ups when travelling to Naples.