I'll vouch for the Diamondback cover. I've owned 2. First was a used SE model. Found a guy with it on his truck that was on Craigslist. He sold me the cover and lowered the price of his truck (I think). It was great but came across a deal on a new HD cover that I couldn't really resist so ending up selling the SE for more then I paid for it.
Before these, I had a fiberglass one. Was a total ***** to take on and off, so heavy and awkward it really was a 3 person job. What I liked about the Diamondback when I first saw them at a truck show was that I can install and reinstall by myself, which I do a few times a year. Like Ryan said, about 5 to 10 minutes to put on and off by yourself. If you've got 2 people and an air ratchet, it literally could be done in 2 or 3 minutes.
Gotta remove mine whenever I go to pick up a ton of wood pellets 4 or 5 times each winter. When I picked up a new kitchen stove, I just folded the back part forward, strapped it down and loaded the stove into the back half.
My brother has an undercover for his Chevy but we are both keeping an eye out for a used one for his truck (new is too pricey for him)
BTW, my great deal on my current cover was $500. I won an SE cover from a Facebook contest Diamondback was running for Christmas a few years ago but paid an extra $500 to upgrade to the black bedlined HD model. Sold the used one for $200 more than I paid for it so in the end, it was about $300 for my cover. The cost doesn't influence my opinion of the cover, loved it even when I had my SE cover. And no, have not needed the extra weight bearing capacity of the HD, not yet anyway.
I'm noticing more and more of these covers around now. Before I would rarely see them, but see them more often now so I guess others I liking them too.