Just got home off 2000 miles in 3 days driving my newly-acquired Interstate Grand Tour Twin 4x4 home to Colorado from Tampa. I insisted on 4x4 due to our home being at 8500' elevation, up a 1.5-mile VERY steep dirt road. That being said, the TIRES are more important than the number of wheels driven. We use Blizzaks in the winter on all our cars, and there are Blizzaks in a 215/85-16. There are also some all-terrain Kumhos I see on Tire Rack that are very highly rated by user reviews, and also have the snowflake-on-the-mountain symbol for severe winter use. I think I may invest in a set of these and use them year-round, though I am tempted to just get a separate set of Blizzaks for winter.
I think the ride-height issue is easily the biggest draw for me in getting the 4x4. It is weird, though, that the front is raised 1.2" more than the rear. It definitely shows, too, with a nose-up stance. This still creates a big opportunity for dragging that long overhanging tail section. I am also looking into the helper leaf springs VS. the Boss airbags on sprinterupgrades.com.
The ride on my trip, mostly Interstates, was rough. I was mainly bothered by a terrible wheel-balance issue (front and rear) but I'd have to say the bumps were very harsh as well. That's the price you sometimes pay for control. However, there could be room for improvement in shocks.
I also experienced the widely-mentioned "soft brake pedal" issue. By the end of the trip I was pumping up the brakes a stroke or two every time I needed to use them, in order to get a higher, firmer pedal. One should not have to do this. Any suggestions on brake improvements would be welcomed.
Anyone try the Boss airbags or the helper leaf springs yet?