It's been a long time since there's been a discussion about covers -- and I'm due to buy one soon.
I have a Sunstar which came with the tub. We got it in -- ready? -- 1998 and only recently has it shown signs of wear. (There was water inside after the last big rain, the top has some minor holes, and some of the skirts are stiff.)
I'm looking at Sunstar, but I'm guessing they're very expensive and only available form dealers.
There are seemingly dozens of distributors online, but it's difficult to know who's selling what.
The one I think may be okay is BeyondNice. They claim to manufacture the own covers. The order page ask lots of questions (I think that's a good thing). Most of the reviews seem legit and most are positive.
I'm hoping for help, ideas, and suggestions.
--Steve