I have tested both cars (4.8) with adaptive drive and not. In Dubai the sport model is just with sporty suspension ie. firmer shocks and springs in the front. The adptive drive comes with air springs all around and the sport button that fimrs the suspension when pressed. To be honnest I did not see any difference when pressing the button, besides I know I would be driving the car with "sport" on always. Now coming fomr the E53 (X5 4.4) that had air springs all around and sport suspension (lower and firmer setting) , I recall that every 35K I had to change the front air springs as they are the ones to suffer most. OK for a new car, but take into consideration what will happen a few years down the road and what if the hydraulics will have to be fixed every 50K or so, or if a pressure valve fails and the car is not driveable anymore. For me, simple things work better and since the sport model proved to me a nimble driving behavior, firm as I want and with no or limited body roll, I made my choice and saved $$ to put them in confort seats that offer the best combination. (Mechanical sport suspension and confort seat), something missing from my old sport E53.
But that again is a subjective choice.... Hope that helps!