We really wanted to get a cover this year for our new Rockwood but my dealer talked us out of it...he doesn't even sell them in his store.
If they do survive the harsh winds here (and they usually rip to shreds in a year or two), the movement from the winds can do a lot of damage to the RV.
He did suggest covering the wheels, awning, and air conditioner. He, also, said to replace my vent covers with a product called Maxxair as they can survive a hail storm while the factory ones do not. (I researched them and it looks like something I can do myself so that's one of my winter projects.) The Maxxairs are supposed to be as tough as the fan-tastic fan covers and you can leave them cracked open and no water will get in.
And, of course, he said waxing the camper a couple of times a year is not optional. (Our Rockwood is pretty big so I ordered a Porter-Cable variable speed buffer to help out...and it will handy with my other vehicles, too.)
I've read great reviews about this RV, Boat, and Aircraft wax by Pro, anybody else try it? (I'll be trying it out soon.)