WTD,
Welcome to the RV Forum! Glad you joined us.
My preference is for stainless steel components, which provide a positive attachment. The choices are snaps or thumb turns or if one chooses to make the cover themselves another choice is a bungee cord combined with stainless steel marine fasteners, with grommet rings in the vinyl cover. I f you would like more info on the do it yourself option, let me know.
I feel suction cups would not withstand wind and UV drying from the sun. My impression is they would dry out and let go. Is it possible the vendor providing the suction cup method does not actually install the cover on site, but rather makes it from an in-house template and sends it to you to install yourself?
IMO windshield covers should be securely fastened using a system that allows you to keep the cover stretched tight. Rubber suction cups might not allow for a tight fit.
These covers give your coach privacy during the day because you can't see in, however at night when it's brighter inside than outdoors, you can see in so you need to draw your curtains.
It's an accessory I would not be without, and my only experience is with a light colored cover which works fine. Looking forward to hearing about how black covers affect temperature.
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