Pignatelli is ideally located for exploring the Historic Quarter of Naples. We (a couple) stayed there for two nights in July, to explore the city. It was hot, and coming back to Pignatelli to make use of the jacuzzi (set on cold, of course) was excellent. The building is set way back from the road and it was very quiet when we were there. There's a basic kitchen we used to prepare a packed lunch for our onward journey, otherwise we were out at Sorbillo's or da Michele - definitely visit those.
A good base for visiting Napoli!