I had an excellent stay at Imma and Pino's place. The location is very convenient with shops, cafes and restaurants everywhere, and it's only a short walk away from the main train station, from which you can easily get the Circumvesuviana train to Herculaneum, Pompeii, Sorrento etc.
The internet was very good - about 150-200mbps download speed. Even better than I had in the UK.
Imma and Pino included a few nice touches - some drinks in the fridge upon arrival, soap/shampoo and plenty of toilet paper in the bathroom.
Only advice is that if you accept the pickup service (you should, much safer than Naples taxis), make sure you agree on a meeting location in advance and get a google maps pin - they're wonderful and very helpful people, but their English isn't great.