Both were excellent. I'm talking about Ragno D'Oro and Al Gabbiano - within a stone's throw from each other on Lungomare Giuseppe Giardina (a.k.a. the seafront).

The second one was remarkable in that the oven had a rotating floor with fire area to the left, visible behind a circular porthole some 15cm in diameter. A large rectangular glass door covered the dome opening. It presumably had forced ventilation - and from the way the flames were moving I wondered at first if it was running on gas (but the chef held up a piece of wood to indicate otherwise). His English was a good as my Italian (i.e. nonexistent), so I couldn't deduce the make of the oven. (But a bit of subsequent Googling has revealed it.)

A little way up the street, just into the Old Town, there was another restaurant at which I had pizza. It was like a wooden disc, having been flattened with a rolling pin! So that place definitely let the side down. PM me if you want the name!

Neapolitan pizza is less common in Sicily than rectangular tray-baked focaccia pizza - which of course is still pretty nice. And readily available in most cafes.