First, good luck at actually finding anything but a base SLE1 model if you actually need an 8 passenger AWD vehicle. The dealer searched and there were no SLE2, SLT's, or Denali AWD 8 passengers (or Buick Enclave's) within 500 miles on dealer lots and nothing in the production queue without having to wait for a special order (at much less of a discount). But after driving a 7 passenger Denali, we are glad we just took a base SLE as there really isn't that much to justify the 14k difference in price and huge difference in residual value.
The problem is with the premium trims like Denali, there's really not that much 'Luxury' to justify the price difference.
The ride is controlled. Not sporty or jarring but not too soft.
The space behind the rear seat is more than most rivals when all of the seats are up. We didn't want to go full size SUV so we looked at the Honda Pilot and new Toyota Highlander since they are the only 8 passenger competition that offers AWD (the Toyota Sienna 8 passenger Van is only offered in FWD). Both have virtually no space behind the 3rd row and getting to that 3rd row is not as easy as the Acadia. The noise level is not quite as low as Buick (which wasn't that great either) but tolerable.
GM really needs to step up the 'Luxury' on these models if they are going to keep promoting the Denali and Enclave as luxury competitors. There is no front parking assist, roll up sunshades for back seat passengers, key-less entry and start, a more modern 8-speed transmission with better fuel economy, thinner seat backs to give 2nd row passengers more legroom, a simple sun glass holder somewhere, and better carpet materials. An GM eAssist feature (like on the Buick Lacrosse) for better MPG would be nice as well as a simple hill descent control on AWD models for going down icy or snow covered hills. The higher HP version engine from the Cadillac SRX would be nice for the Denali.