We have visited history museums in other European cities and this one is definitely one of the better ones. We only had about two hours to visit this museum. We could have spent half a day.
The museum is well-curated. Some highlights: You can experience being in a bomb shelter while bombing occurs overhead and walk into a bunker. Additionally, there are life-size figures of men who played critical roles in Sicily's history during WW II. There are a collection of uniforms worn by the soldiers from various countries. A relief map with an overhead projector shows the day to day advancement of the Allied Forces.
Should we return to Catania, it would be worth our time to revisit this museum.