I am using the elitemotoronline ShieldAll cover on my Boler
1700. We'll go one more winter for a total of three winters, and then we'll have to replace it.
It starting developing some short rips after a year or so, and we've been patching those, first with a sewing machine and then later we started simply using clear gorilla tape.
The zippers have not ripped out or failed in any other way. Just have to be slow and methodical while zipping and unzipping. Applying wd40 silicone or just cleaning would probably help with zipper operation, but we haven't done this.