Will I do not want to be a downer but save the money and use it on something else.
What you need to realize is that most cover will move around slightly do to wind when in storage. As the wind blows and the cover moves this will wear the material/paint under the cover; such as the roof corners. Moisture can also be retain in some cases which will lead to mold/mildew. Another problem is that most covers only last between two and three years and then they need to be replace.
I have own two other 5er's and I am on my third one now and I have never use any covers at all. Do dealers store their used and new trailers under covers before they are marketed for sale? Do full-timers use them as they stay in their fiver?
We picked up our new 5er this week and the DW asked the dealer principle and our salesman if we needed a cover for the 5er. They both stated don't buy one they are a waste of money and wear the roof material corners.
Just my very humble opinion.
2016 34RL CC; 2008 Ram Mega Cab 2500HD, 6.7L, 68RFE 6 speed, 4X4, Smarty S67