If you're going to do real off roading, the Quadra-Drive II is big boon, that is the one to get.
The clutches in the ELSD's will make noise if the axles are overdue for a fluid change or the fluid was changed and NOT enough of the friction modifier was added to the axle fluid. So if you have noisey (chirping) axles, insist they change the axle fluid w/ the right friction modifier before buying, so you know its just fluid and NOT a serious/expensive problem that requires fixing.
The V6 makes as much power of many V8's of only a decade ago, BUT the Commander is very heavy. Because of the weight and aerodynamics mileage is poor, and the engine management does well enough that there is really not much difference in mileage between the engines. So depends on your intended use. But if you're going to hual, or do serious off road, then you want the power of the V8 to lug the heavy loads.