The basic problem with any kind of cover is that it rubs on the aluminum when the wind blows, which causes ugly marks that are very hard, if not impossible to buff out. This is especially true on older trailers that are clear coated, and newer ones that have the (so called) permanent clear coat. The coating gets damaged by the motion of the fabric, and any dust under the fabric acts like a crude abrasive, making the situation worse...
A polished vintage AS has the issue of scuffing as well, and a further issue that although the scuff may be buffed out sometimes, you will eventually burn through the surface layer of shineable aluminum...
Covers also trap moisture next to the AS.
Rich, KE4GNK/AE, Overkill Engineering Dept.
'The Silver HamShack' ('07 International 22FB CCD 75th Anniversary)
Multiple Yaesu Ham Radios inside and many antennae sprouting from roof, ProPride hitch, Prodigy P2 controller.
2012 shortbed CrewMax 4x4 Toyota Tacoma TV with more antennae on it.