I have done the 7 hr Backstage Magic Tour and it is a really great Tour.
Because you get to see Backstage in 3 Parks it is well worth it.
I have also done the Keys to Kingdom Tour which is also a really great Tour. So it really depends on whether you want to spend 7 hours on a tour or if you would like a shorter tour. The Keys to the Kingdom tour is only of Magic Kingdom.
Both Tours when it comes to the Magic Kingdom do cover a few different things.
I know this probably hasn't helped much because they are both GREAT Tours. It is a personal decision. Lunch is included with both. The 7 hour BM tour is at a restaurant and the Keys to the Kingdom Tour is at a Quick Service Restaurant, but they do block off an area.
Good luck - it's a touch decision to make.