Was a $2000 option on my 2019 MS order (built 03/201
, was told it added about 200-250 pounds.
The availability of a fiberglass roof was key in ordering a MS over other brands, as well as being able to semi custom order.
As Terry mentioned above tree branches will for the most part just bounce off and scuff the paint a little. Compared to the same branches catching the rubber roof and ruining your day.
And if it is the model years with the 3/8" plywood sub structure, the fiberglass roof would take care of the radius side panels popping up through the membrane.
You will probably see the same answer with several items.
Washer/dryer (combo or separates)
Dual pane windows
etc etc etc.
For the most part, those that have the options consider them essential items.
Those don't have them consider them a waste of money.