Two SUVs with more similarities, such as the body structure, starting price, and ground shadow size, than differences, like the horsepower, fuel economy, height, and maximum occupancy. First of all, the 2015 GMC Acadia has a more powerful engine and gets 4.5 mpg less than the 2016 Mazda CX-9. Also, the 2015 Acadia has a slightly taller body than the 2016 CX-9. And finally, you'll seat one more passenger in the Acadia than in the CX-9. Among similarities are the body structure, starting price, and ground shadow size.