We stayed at Travicelli apartment and we had a wonderful time. The apartment is situated very central in the old city, which makes a city trip very comfortable. The apartment has everything you need and did answer to our expectations. The description on the site is accurate. The apartment was very clean, there were some groceries to use the first day (very convenient). And above all Francesco is a very welcoming host. He arranged a taxi for us for a transfer from the airport, which was nice because of our late arrival. (the bus from/to the airport is also very convenient and the train station is close by (10 min walk)) Francesco offered us even to buy pizza because of our belated arrival.
The apartment is well situated in a typical Palermo 'vicolo', next to the lovely piazza San Domenico and the Vucciria mercato where you find all kinds of food for your own cooking. Lot's of nice places to go for an 'aperitivo' in for example Via A. Paternostro, where you also will find lots of nice little shops with 'artigiani' work.
When I return to Palermo (which I will surely do, because I fell a little bit in love with the city and the Sicilians), I would definitely like to stay in Francesco's apartment again.