In my experience, this is not quite accurate. I first installed vinyl (they are not leather) bras on customers' Porsches in the mid 70's, and have used them on all my cars as well since that time. Paint fading is only an issue with misuse; specifically, it's the result of letting the cover dry in the sun while installed on a stationary car. If left in the garage or other cool, shady place, it's not necessary for a wet cover to be removed, nor is there any problem with it drying on a moving car. I've dried the front covers on my cars many times both ways with no ill effects. In addition the bra needs to fit properly, with no chance of it rubbing the finish while the car moving. Finally, both the paint & cover must be scrupulously clean and dry prior to each installation. Follow these simple practices, and the better vinyl covers are unbeatable at protecting the front of your car, even from hazards that will punch right through a clear or nylon solution..... The leather bra I feel are bad on you CC. Makes the CC fade if you leave it on.
The keys with any removable bra is to: (1) not leave it on the car all the time (use it when you are going to be traveling on highways a lot in particular, (2) keep it clean (another responder said wash it peridoically-very true), (3) keep the finish clean and waxed/polished udnerneath the bra to prevent scuffing or fogging of the CC.I've always heard that the nylon/leather type covers get dirt underneath them and you risk scratching the paint underneath from it "rubbing" while air is passing over it.
Have you had problems with that?
Lamin-x head light and fog light covers address this...No substitute for the 3m clear bra, also protects those expensive headlights. those strap on bras does nothing to protect the headlights which are pretty expensive.
Like most items affecting appearance, this is a matter of personal taste. We were all set to install a clear bra on Nancy's new C6, and bought the factory bra just to protect the front until that was done. Now she says she likes the look of the GM piece & doesn't see any reason to spend the money on another solution. Weigh the trade-offs between the various types & buy what you think suits your needs & preferences.Don't kid yourself, any strap on bra makes the car look hokey.