I'd say this place was ok!

The lobby/bar/breakfast-restaurant area looked pretty nice at first impression. However, the rooms are where the disappointment really comes in for this place. They are quite dirty, there are leak marks in the bathroom ceiling and very old. Overall they are ok, but could really really need to be updated at least a bit. Air condition could not be turned off and it could not produce cold air.
Also, the bar wasn't that very good either, lots of drinks, fancy stuff, but the bartender does not have the ingredients to make all of them.

I would however come back here because all in all everything was ok and you've walking distance to restaurants, 10-15 min or so.

I’m totally satisfied with our stay at the NH Ambassador Hotel Naples. The hotel has the best view in Naples, one can only desire. It opens a panorama of the Gulf, Vesuvio, Castello Nuovo with magic lights of Naples, which are admirable, especially at night. While booking, choose the highest floor and the "Vesuvian" side of the building. The room I stayed in was a comfortable suite with two large windows. Staff is friendly, breakfast is good, and I have nothing to complain about.

I decided to stay at NH Hoteles during my current visit to Naples, thanks to a recommendation by a friend. Just to describe the experience -

The hotel is at a convenient location in the city, vary close to the Port and Nuovo Castle. The central railway station is also just 20 min away. There is a Carrefour store at walking distance from the hotel, in case one wants any essentials, fruits, etc. The hotel and rooms are not exactly new, but manageable for a stay. The staff in the reception is a bunch of old, friendly gentlemen.

The rooms are clean and the room where I stayed had a good view of the port and Naples bay, given that this hotel is one of the tallest buildings in Naples. Breakfast was, as in many budget hotels in Europe, exactly the same every day. The same scrambled eggs dish, exactly the same juices, croissants, bread, etc.

The place where the hotel was lacking is the ventilation. Due to winter, the hotel has kept the central AC off. This means that even if air at normal temperature is required for circulation, the facility is not there. So every day, I would keep the window open for an hour for fresh air to circulate in the room, and then close the window for the night. Next morning, I would open the window again so get the stale/static air out of the room.

Wi-Fi internet is available for free for 30 minutes in the lobby, in case one wants to access the net for any important work. But in case of wanting the net for a longer duration, it is preferable to take the package for a day (10 Euros) instead of for an hour (6 Euros).

I had enjoyed staying at other NH Hotels before, so I was really looking forward to my stay. I was really disappointed when I got there: the rooms had not been updated since the 70s or 80s, cheap dirty rugs, broken tiles and mold in the bathroom. Wi-Fi did not work in my room, which was very inconvenient since I was travelling for business.