It's a museum for one of the most tragic days in U.S. history. So, go there knowing that there is an inherent sadness to what you'll be viewing.
However, it is also a very special place. The museum creators have taken time to tell so many stories of people who were connected first-hand to 9/11. And, the exhibits are also hopeful, as they take time to tell of the many good things that have come about as a result of that day in history.
Compared to the National 9/11 Museum, it is certainly cheaper; but there are also not as many artifacts. However, we found it extensive and informative enough that we did only this museum and we do not feel as though we missed out on much by skipping the national museum.