We loved the tour, and we thought well worth the money.
You are correct, it started at Epcot, then MGM ending at MK. Some memorable things include seeing inside the ride mechanism for Body Wars (no wonder it makes me sick!) and the mechanism for American Experience. We saw a lot of backstage stuff - custom costume design and creation, the shops that create all the custom millwork, statues and things like the cars for the rides (they were rehabbing the Hunny Pots when we went through). We saw the shop that paints the carousel horses and one that makes signs. We also toured the warehouse were they store ALL of the christmas decorations for the entire resort. There were ladies there working on Christmas items and that was in May. The tour also takes you through the utilidors in the MK, and you stop to see the afternoon parade. Lunch was at Mama Melrose in MGM where they brought out tons of different kinds of appetizers, pizza and pasta and dessert. We just passed the platters around the table family style.
Overall the tour was very informative and I'd highly recommend it for any Disney fanatic.