We have not had a minutes trouble with our 6 cyl Mercedes engine (2013 chassis). We like everything about the Mercedes and the Winnebago portions (we did add HWH automatic levelers). It has about 14,000 miles and I changed the oil myself at 10,000. We weren't having any problems but I did read there was a software update for the computer and took it to our local, 30 miles away, Mercedes dealer and they did it under warranty. I believe they started a new design that uses DEF in 2010 and there is not a bit of soot or smell in the tailpipe.
You will read about some complaints (some of them from the owners but I've noticed that a lot of them are from people that don't own one and aren't that familiar with them). In my opinion, there aren't many used ones for sale compared to the number out there on the streets....and that says a lot for customer satisfaction.
There are 3 View-Navion groups (
General ,
Technical , and
Mods) on Yahoo forums that may be worth looking at. This subject has been on there before and the general consensus seems to be that one is much more likely to complain about bad experiences than to write about good ones. I'll write a reply like this occasionally but have never just started a post about how happy we are with ours.
Good luck in whatever you decide.