We have an Adco cover on our 43' coach and it works perfectly. We did buy the warranty as no cover is going to last three years in our heat. So for the cost of the warranty we will get a new cover. We did that with our previous 38' coach. I know there are a lot of nay-sayers about covers but from my experience using one religiously for the last six years we have had:
No damage to the paint or finish of our coach
No issues with tearing(I do cover a couple of sharp edges with tennis balls :-) ) Keep in mind, we have wicked monsoons and still no problems.
We replaced ours because the straps got dry-rotted and ripped in two eventually.