I remember this mentioned on another thread, but forgot which one. The narrower wheel width is an issue with the new Euro-van coaches. The Transit, Sprinter, and ProMaster/Ducato are all designed with a narrow axle so they can handle the tight curves and narrow cobblestone paths in Paris or London. However, in the US where highway speeds tend to be faster in general than Europe (Autobahn excluded), the narrower track width can be an issue.
One odd thing: I've been reading about the ProMaster, and people saying it is a fairly stable vehicle on bad roads and inclement conditions. This is surprising because it is a front wheel drive vehicle.
Time will tell... I'd like to see some Winnebago Trends get into the hands of a few people to see what their stories are about the rigs before I go that route.