they dont show you too much magic. because well..that would just ruin it all.
but they do show you how the different striped colors on the wall let you know where you are (ie: red white and blue is liberty square, bright purple is tomorrow land, dark red is main street, fuschia is fantasyland, etc...) they also show you where some break rooms are, how people get to "wherever" so quickly, etc.
i dont want to blurb about how the utilidor looks so just in case someone wants to be "surprised" but they'll ask you what you think utilidor means, etc. oh, and i know they dont do tours at night, but they always play the radio in the tunnel and at night we slow down and love someone with delilah ;] (its...one of our...cm..jokes..anyway!)
really, its up to whatever you want to do. both tours are excellent and worth the money. :]