We drive to several ski vacations every year and pulled a 21 foot boat for the first two years. Love the 4wd in the snow and getting the boat out of the water. Mechanical - two sets of brakes, a loose antenna wire and a stuck thermostat are it for maintenance.
Exterior style, the 4wd, back seat radio control and height & size of the back storage area. Stuff that goes in my Explorer won't fit in my friend's Envoy. Almost no maintenance except as recommended by the owners manual.
Better emergency handling. I understand that's been fixed in the new models. Engine should have more torque, maybe a high tech inline 6?