This place is amazing. I wasn't sure about the Vesuvius view while booking, but it's clearly visible from the balcony. The best part of the place is the apartment itself. It's a new and shiny apartment with pretty much every amenities you'd wish for. Two bed rooms host 3 person, while iguess a 4th can take the couch, if needed. There's a dedicated parking available in front of the house, big enough for any sedan/suv. Moreover, there's another dedicated parking available on the basement, where you can lock the car up. Trust me, when you're in Naples, you'll know why this might be a good idea :P
The hosts (Rosanna and her husband) are great. They were readily available on the phone for any queries. Gave us local tips about what to do, how to do, places to eat, etc. We actually ended up extending our stay :)
Location-wise, the place could be bit tricky. The train station is 10-12 min walking distance, there's a bus (154) as well, that goes to the city from the same place. You can take another bus (254) to the station. I am not sure about the frequencies, but on the weekdays we found buses running every 20-30 min and as late as 9pm. Other option is taxi, for which host has a negotiated price (i didn't use the service though)! We used the public transport for the city, and our car to visit everything else, e.g., Pompei, Vesuvius, Sorento, Positano, Amalfi.
And lastly, wifi works, and good enough to stream high quality youtube. Enjoy your stay.