I went with a friend and neither of us had any idea what to expect. We thought it would be a museum, similar to the Atomic Testing Museum or Bellagio Gallery of Fine Art. So, we were very pleasantly surprised to find that it's actually an interactive experience along with educational displays.
We went in the late afternoon on a Monday, so there was no line. However, if you did have to wait, the queue has several info screens you could read while you wait. You get a nametag with your mob name and are escorted by actors through some areas - you're being tested to see if you have what it takes to join the mob!
It's fun and the actors are good about not breaking character. Mess with them; they're really fun about it. Eventually you get to the museum, where you can spend as much time as you like. There is a room dedicated to each mobster. A few of the screens weren't working, but there was so much to see that it didn't bother me. If you get tired, you can sit down in a theatre and watch a documentary about the making of Hollywood mob movies.
Once you leave the museum area, the "experience" starts up again. You can even blow up a few casinos if you want, ha. I won't spoil anything for you.
Does it glamorize the mob? Not really, but it does not really show the violent and horrible side of the mobsters. You're looking at their baby shoes, not pictures of their mutilated victims. Of course, many mobster's widows and kids are on the experience's board of directors, so they probably have quite a bit of say-so in what is written.
Yes, it's expensive, but lots of fun. Allow at least 2 hours to see everything.