Wife drives an '07 Suburban, and I traded my '08 MDX in on this Denali XL when we had baby #4 (too hard to use the 3rd row). Love the Denali, but have to say the '07 Suburban is faster off the line by a considerable amount, even after giving up about 90 HP. Must be the AWD and 20" wheels on the Denali. And as much as I love the exhaust note on the Denali, some folks may not appreciate that and go for the relatively quiet 5.3L engine in the Suburban or Yukon XL.
Rear view camera (no distortion, like my MDX had); cooled seats; 3rd row DVD screen; fact that I can watch movie on nav screen when parked.
Love the leather bound door handles...wish rest of door & dash were similar. And of course, better mileage, but no HP loss!