I recommend Giorgio and Nancy's place without reservation. I am an academic and was a visiting professor at the University of Catania for three weeks and this was the perfect place to stay. It is ideally located, two minutes from the Roman Theatre (be sure to visit!), three of four from the Sicilian baroque splendour of via Crociferi, and five minutes from Piazza Duomo.
The place is spacious and the fresco on the ceiling of the main room is a delight. It would be very comfortable for a family of four or even five. Communication was easy, and there was a quick and favourable resolution to an initial misunderstanding. As such I highly recommend their place as I do the delightful city of Catania. A real hidden gem.