On another note....Wondering if the ride would beat you to death on a long trip in the Unimog. I'm sure it has suspension seats, but still...
I had one test ride in a U500 and it felt fine when it had some weight on the rear. (One of the U500 guys will, one hopes, provide more detailed information.) Empty, any Class 6 or 7 truck is going to be harsh; the Mog seemed much better than most.
As a class, Mogs are generally cushier than you might expect. Suspensions are fairly compliant and most Mogs are running on large tires that don't have to be inflated very much to carry the weight, so the tires act like another suspension component.
Some Mogs have very short wheelbases with all the choppiness that implies. But in the longer-wheelbase trucks I've been in, the ride is more than adequate. (And my own Mog camper, which has an unusually long wheelbase, rides like a Cadillac.)