I've got a 2009 2500 Suburban. I went with the GMT900 so the transmission would automatically downshift when braking and on cruise control. This will be important if my wife drives it towing the boat while I am towing the camper.
There is no AFM on the 2500s. The vehicle does a great job with our family of 5 and a 6,500 pound boat. It's got 153,000 miles with no engine or transmission problems.