In short, a terrific host in a terrific location and an unbelievable view from a huge terrace.
Annamaria's home is like going to visit family. Breakfast is fresh fruit with the most amazing homemade pastries and homemade marmalade. Location is close to the funicular and metro stations (and there's a street-level escalator from the metro) and good local restaurants; a haven away from the touristy historic center. The view from the terrace is everything! You can see Vesuvius, Capri, the Amalfi coast, and amazing colors at sunrise and sunset. Also, Annamaria's breakfasts of homemade pastries and marmalade deserve another mention. :)