The MAS hosts a bunch of different collections, these used to be in different other places. Yes you can see a lot of different collections in the MAS and yes it's a spectacular building.
But: 1) there is no natural light inside 2) the museums where the collections used to be are closed not. One example: "het steen" was the perfect location for the harbour / boat collection, you can see this collection in the MAS now but only a smaller portion of it and the old castle alike fortress build near the schelde was the best possible location... . All together it's nice for tourists who like to see a lot in one place but you loose 25-50% of the collection and the charm of the original buildings (with special characteristics, natural lights and off course the specific negative points we all learned to live with).
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.