We try to visit while in Europe whatever can help us understand WWII better, whether going to a museum or a camp or a specific tour related to the war. We had to research to find places in Rome and we visited this museum before going to the one in the Jewish Ghetto. No, it's not fancy, and most of it is in Italian, and the English audio guide doesn't always sync up with the numbers on the pictures... but it's pretty clear that this place is a labor of love. And if you are sincerely interested in becoming educated--especially as an American tourist who has not experienced being occupied by a foreign nation--there is much to contemplate here.
The museum is bigger than we expected, and filled with artifacts. There is enough English to understand most of what is being presented. It is a somber place, and you look out the windows on this nice street and can think for a bit about what it must have been like to be locked up and tortured while some semblance of life went on outside.
If there was a hefty charge to visit I might understand some of the complaints about language accessibility, but there is no charge (though donations are appreciated). There is plenty to see and reflect on. It's too damn easy to forget how bad people come to power. Highly recommended.