Napoli is a city that’s changing very quickly and even piazza Garibaldi (the bit outside the station) is improving. I think it’s better to rent an apartment than a suite in a hotel; the city doesn’t have, in my opinion, that crop of big international hotels that American/overseas visitors are mostly familiar with.
If were to stay there for a week or so for working I’d stay at the Vomero or Posillipo: high up, scenographic, lots of sun.