A tidy, nice flat in a puristic style - a lot of interesting sights/ locations are easily reachable on foot, but the train station Monsanto and the metro station Dante are very close by in case on foot is too troublesome or, e.g. you want to leave Naples for a day in order to visit Ercolano or Pompei.
In my opinion a safe neighborhood - I was travelling with a female friend and we never had any reason to worry.