One thing I do not like about the Caddys are the rear 3rd row seat. You have to take them out to get that extra storage.
The QX56 will pull/tow more.
The Caddys have 6spd but they don't really get all that much better gas mileage so what's the use with that?
Here in my town Escalades are all over and you don't see any 56s.
I use to have an 06 EXT and now I'm getting the QX56 soon.