There is no overstating how great this flat is and how hospitable Stello and Carolina are. The location speaks for itself: it is in the heart of the historical centre of Palermo, in a piazza with good bars and restaurants, and yet the apartment is incredibly quiet. It's literally two minutes away from the stop of the free bus that circles Palermo's historical centre (one of the many great tips Carolina provided). There's a great pizzeria literally downstairs!
It is certainly the most stylish apartment we have ever rented on AirBnB: beautiful, bright, spacious and tastefully decorated, with amazing tile floors and a very comfortable bed. It's fully air-conditioned (we were there in a very cold time, so we used the split air conditioners as heaters) and very well-equipped to the minimal details.
Stello and Carolina were exceptional hosts: we checked in relatively late (10-ish pm) due to our flight time, but there were not complaints or extra charges (so common in AirBnB) because of that. In fact, they were both there and took their time to explain the city's transportation system, offer us many great guides to the street markets, the various architectural landmarks of the city, the museums and so on. Carolina recommended a great puppet museum, which our 3-year old simply loved!
I will not think twice before booking their flat again in my next trip to Palermo.