Our stay at Nadia's was great! It was right by an excellent food area, and about a 25 minute walk from grand central terminal. Plenty to do within walking distance - food, shopping, and museums!
The location was very safe; there were 3-4 secure, keyed gates to go through (the 4th was when the large doors into the complex were shut for the night). The narrow exterior walkway overlooking the courtyard was a bit tough to navigate through with luggage, however it is a small price to pay to have such a perfect location!
I highly recommend trying out some of the restaurants and coffee shops, and taking the short walk to the shopping district! We were only a 15 minute walk from the Naples National Archaeological Museum and the entrance to the Naples Underground- so many great things to do nearby! Also about a 15 minute walk to a smaller train station if you are headed to Pompeii.
I strongly recommend eating out; we had originally planned to do more cooking, however kitchen prep space is tight, so we went out to eat instead (which you won't regret-there are so many great restaurants nearby).
The jacuzzi was amazing, and such a welcome place to relax after a long day. Pro tip: start filling it up early; the tub is huge, and takes about 75-90 minutes to fill up. We were frustrated how it took to fill up the first day but loved it once we knew to start it much earlier.
Paolo, Nadia's counterpart, was mainly who we worked with; he met us for check in, explained the 3-4 keyed security gates and which keys to use to get into the apartment, and was great about giving us the tour of the place. He took time to explain how some of the features work, and let us know to call if we needed anything.
Check out was easy; they had a sign saying if they couldn't be there to check us out, to leave the keys in the table and take the trash out, which we appreciated- we had a very early train and loved to have a self checkout option!
We didn't interact with Nadia aside from setting up a check in time (we originally thought we were much closer and would need to check in early, and she was super accommodating about it, simply asking what time we would like. While we didn't end up needing to do early check in, we definitely appreciated that she was so flexible on it), and we interacted with her briefly on the last day when she texted a morning reminder that we needed to be out by 11am (we had actually already checked out at 7am and had already let Paolo know).
Very few complaints; only ones were the walls were very thin - we could hear the neighbor's cellphone vibrating and them talking very clearly during our stay. I also wish there were cleaning supplies; usually I clean before checking out and felt a bit guilty that we couldn't do so here.
All in all I recommend Nadia's place; the location is great, and it housed one of the best jacuzzi tubs I've ever seen (and she included padded headrests for the tub- no sore heads here!)