We have been researching a little on the different Class C's and have noticed that the upper priced ones tend to have the roofs and the walls constructed of fiberglass, while the frames are wood and rolled steel. Are these actually better construction than one with laminated aluminum. How does fiberglass stand up to the sun and road hazards (small rocks)? Also the upper ones use spun fiberglass as wall insulation rather than polystyrene foam. Is it a better insulator or just lighter? Right now we are looking at the Lazy Daze and the Born Free (actually here in Nevada!). Thanks for any help.