We had a great stay at Caterina's and would highly recommend staying at her place. The location is great - very central and the flat leads straight out into the market (though it is still amazingly quiet inside!).
It was clean and nicely furnished and had everything we needed. We enjoyed some evenings in the flat eating food from the market outside.
Caterina kindly left us little extras like some fruit and milk when we arrived and her husband really helped us when we arrived and were looking for the car park in the middle of the night!
A great place to stay in Palermo.