I did the KttK tour last week and it was fantastic. I have done the tour before and the thing that I love about it is that the tour guides make it their own, they add their stories and experiences.

You get a gold key shaped pin to keep and is not avalible to buy.
IMHO it is well worth the money for the experience and especially the back stage areas.

On my latest tour we went on Jungle cruise, Pirates of the Caribbean and Haunted mansion. You get to go backstage behind Splash mountain and see the parade float storage building, splash and the boneyard! You also get to see the famous Utilidors! The other great thing with the tour is that you don't know what and who you are going to see backstage and also the other guests who are on the tour with you.
Lunch is included at the Columbia Harbour house.

The thing I would advise you to do is to go for the 8:30 tour beacuse you get to go into Magic Kingdom before the park opens and get some great pictures of a deserted Main Street