The Mob Museum was very cool. Very good, in depth exhibits and short films giving you an in depth look at what the mafia was, and is all about.
I would recommend the basic tour as it is more price friendly and you still get to see everything that it important.
Plan to spend 1-1/2 to 2 hours looking and reading about all the crime figures. Open late. I don't think kids under 12 would enjoy the museum.
More for teenagers that like to learn about the Mafia.