I have used Storm force covers in the past. Well made, fitted to car model, lasted about three years before needing repairs (I live in wet and windy area). They have to be strapped tight to avoid wind moving and causing chaffing on paint. Where the straps go, under the sills, add a bit of additional padding to avoid damage there. All in all though, they did a good job and were breathable, so didn't cause lots of condensation and it's associated paint marks. I found them good for cars getting stored for a few months, but too much of a pain taking off and on for cars being sporadically used. I think they were better than nothing at all as they kept bird muck off, but prior to the covers the cars in question survived well enough due to some rust proofing done each summer. I'd use them again if I had to.