My friend and I spent a wonderful five days at Giuliana's place. Her apartment is beautiful and modern and we loved hanging out on the outdoor patio on the roof (with a view over the rooftops of the Quartieri Spagnoli, and of Vesuvius!). Giuliana provided all the amenities we needed (shampoo, conditioner, and body wash in the shower; bottled water, although we just drank the tap water; etc). Although it was fairly hot when we were there, with a fan in the window and both windows open we slept just fine, although the bed is a bit on the hard side. The location is perfect -- very close to Via Toledo, one of the main shopping streets (and a metro stop), but still far enough into the Quartieri Spagnoli that you feel like you're living in a "real" part of the city.
One thing to note is that this is a fourth floor walk-up, so keep that in mind if you have large and heavy suitcases (like my friend did, although Giuliana graciously helped her bring it upstairs). You also need to walk slightly uphill on cobbled streets from Via Toledo to get there.
Giuliana was an excellent host, her apartment is lovely, and I would absolutely recommend her place to anyone wanting to get a real taste of Naples on their next trip. Grazie di tutto e spero di tornarci presto!