I have experience with both.
I still have the Cabelas one and it has been a very durable cover for me. It has the zippered openings at the top although i don't use those much. The waterproof coating they have on the underneath side stands up to the test of time for me.
The Otter one lost it's waterproof coating after 1 season. My son still uses it on his flipover but it looks more like a black "see through" sheet now and it starting to fray around the edges.
Both of these covers are about 5 years old. The Otter looks it's age but the Cabelas one doesn't.
One other feature I like about the Cabelas one is that it has an adjustable bungee cord that snugs up tightly or can be loosened and re tightened to adjust for different amounts of gear stashed underneath it.