Just sold our 2007 (received it late 2006) Rockwood TT with a vinyl roof. It lived in the FL sun the entire time. Roof was washed about once a year. I replaced the LAP sealant a couple of times. Roof still looked good.
Bought our current RV. Fiberglass roof has cracks where it meets the sidewalls. Too sharp of a radius. Contacted Lazy Days a week after purchase, they were no help. Their 30 day warranty means nothing.
Contacted the manufacturer, though it was only 3 years old at the time, they said they wouldn't cover it. But the year newer model, they have a TSB to fix it. Well, not really fix it. Cover the area with an extruded piece of aluminum, then seal it with a roll of Eternabond. Forest River dropped the ball on this one.
So don't get too excited about a 1 piece fiberglass roof. In theory, they should last longer than vinyl or EPDM... but poor engineering can directly affect that!
Video of the issue with ours:
https://www.youtube.com/watch?v=m5ibP-7t6-oAlready had some water damage to a cabinet. I've since sealed the area with RTV. When it cools off, I will fix the fiberglass area properly myself, building up and smoothing the affected areas. It's not complicated to repair, but it's also ridiculous that I have to on something so new. Even Ford still has a chassis warranty on this vehicle!