Elisabetta's apartment was utterly fantastic. It's a beautiful, well maintained, clean and open space. And it just happens to be right in the center of everything. I don't think you could ask for a better base location in Naples - right by the Piazza del Gesu, it's only about 1km walk to the Museo Archeologico in one direction, and 1km in the other direction down to the shore and Castel Nuovo/Teatro San Carlo. Very close to a grocery store and about a million wine shops (including one right next door), and with the equipped kitchen, it's very easy to save money on cooking - especially if you're getting your veggies from the market right nearby.
Be aware, though, that being right in the middle of everything does come with some noise (more so on the weekend, much less on weekdays). The double-paned doors to the balcony do an excellent job keeping most of the noise out, but if you are particularly sensitive to noise, don't forget your earplugs.
Elisabetta herself was very nice and available - even leaving a cell phone in the apartment for us to use to call her so we wouldn't have to use our own (expensive) roaming minutes. She was very responsive to all questions, easy to communicate with about check-in/check-out, and made sure the woman giving us the key was right there when we arrived.
She also gave us a great recommendation for parking nearby that was much cheaper than we were expecting. Be very careful, though, if you plan to drive! The ZTLs are everywhere and it is often very difficult to tell if the route you are taking is going to suddenly pull you the wrong way for a hefty ticket - and with the crazy Neapolitan drivers there's no time to stop and read signs.
We will definitely stay with Elisabetta again the next time we are in Italy!