I took the Backstage Magic tour at the beginning of this month. It was an incredible experience, worth every penny.
My guides were Tiffany and Harry. They were both full of knowledge and enthusiasm for the Disney parks and the Disney company in general, and they were super nice people.
They have now replaced the Hollywood Studios and Horticulture portions with going backstage at Rivers of Light, and lunch is now at Tiffins, which was an amazing meal, so the stops are as follows:
Epcot - American Adventure
Creative Costuming
Rivers of Light
Lunch at Tiffins
Central Shops
Utilidors
While there's not much time spent in the Utilidors, the rest of the day certainly makes up for that.
I have not yet taken the Keys to the Kingdom tour; I may do so on my next trip just to see how it compares.
It's worth noting that you do not need park tickets for Backstage Magic, because whenever you enter a park, you do so from backstage, whereas you do for Keys to the Kingdom.