We did this last November and it is very beautiful. I would suggest going to the second or third show of the night because it nice to see in the dark. First, all the members walk into the theater holding lite candles and singing and make their way up the stage, the center members forms what looks like a tree. Each night there is a guest speaker. I would say the show is 80% singing and 20% talking. The guest speaker tells the story of Christmas (usually speaks just a few lines) and then the chorus sings. The guest speaker speaks a few more lines and the chorus sings and so on though the whole story.
Depending on when you go it gets very crowded waiting on line to get in. We did the dinner package last year, we saw the second show and then had PS for Rose and Crown. This worked out just right as we were eating dinner outside on their patio just as IllumiNations was going off.
Linda