The National Weather Service said that it could be up to dime size hail, but what we saw on the ground was from BB size up to some marble size mixed in. It also broke a few windshields. The two fiberglass roofs that I got up on the ladders and looked at had dents with cracks radiating out from them, and one had a spot where the fiberglass was shattered in an area about 3 inches across.
Having said that, a fiberglass roof is better able to resist a lateral impact (like from a tree branches), while a rubber roof stands up to vertical impact better. There are always plusses and minuses to everything.
I'm told that the rubber roofs weigh less, and I guess that it's better to have less of a weight load up high, for better stability.
Comes down to what you're comfortable with, and as I said before, the two year warranty was the tie breaker for us.
Whatever you decide, enjoy it and be safe!
2016 Redhawk 26XD
Me, Dear Wife,
2 Bluetick Hounds
1 Newfoundland / Black Lab Mix
1 Cairn Terrier