The one thing that’s an issue about the fiberglass construction is condensation below the mattress if you’re ever somewhere cold and damp.
It’s enough of an issue that Northern Lite has started shipping their campers with a “Hypervent” pad under the bed... but those are marginally effective at best.
What works is a thing called the Froli bed system. It’s like $400.
Froli The good thing is these WORK and make the bed more comfortable which is always great. It adds a few inches of mattress height but the Northern Lite has so much headroom in the bed it doesn’t matter.
If you don’t put this in, when you store the camper in winter it’s advisable to put something under the bed to allow airflow.