Hello,
Am living in Dubai, and own a 2009 SEL Eadge.
I have tried it on deep sands here in Dubai, and it was doing not bad at the beginning on not very deep sand.
However when it reach to a serious sand (not dunes yet) it got stuck like any 2WD car, yet I’ve not tried it on sandy dunes.
I have tried it again on different place at different time of the year, and very much the same (couldn’t do the heavy stuff).
What I’ve notice is that the Edge stuck on the sand not because the 4WD is not working (you can hear the sound of the AWD working) but because the car is low to the ground comparing to other 4WDs so the sand hit the chassis very easily causing a big load on the car so its stuck.
Hope this will answer your question.