The Newmar is not a laminated unit, the Tiffin is. If it's Laminated it can (and someday will) delaminate. That someday may be in a year, it may be in 25 years, but it's glued together and someday that glue will fail.
The Newmar is built using a hung wall method. It uses aluminum studs on 16" centers with headers where needed. It can never delaminate.
Take a walk around any campground and look at the older units. They all look good when they're new, so look at the 10-15 year old and older stuff. We're currently camping next to a 14 year old Dutch Star and an 18 year old Mountain Aire. They both look brand new.
When my parents were shopping for what turned out to be their last MH I had fallen into the Tiffin hype and recommended one. Like so many that one too made the trip back to Red Bay for repairs. The repairs didn't last long enough to make it home, I ended up doing them in my garage. I worked on that more in the 5-6 years they owned it than I have all our Newmars combined (3) since 1999. It seemed it wasn't anything major but it was always something.
Friends of ours also fell into the hype and bought a beautiful Allegro Bus. After a number of trips back to Red Bay they finally gave up and went back to a Winnebago. The final straw was when the sidewall cracked by the slide and that "fix" didn't last the trip home.
We don't have the most RV experience, we don't have the least. I know a lot of people love their Tiffins. For me they're not even on list of builders I'd consider.