If you search through kindleboards.com's accessories section, you'll find dozens of posts on their stuff. Most people tend to be happy with it, and a few have also purchased Oberon iPad covers.
My personal experience with their Kindle cover was meh, I think they're way too heavy, there were obvious wear marks on the spine of mine within a month's use, and I didn't like the corner-strap and elastic based retaining system--though I can't fault it's protectiveness. My Kindle hit both concrete and tile while in that case and sustained no damage at all. No way it's going to fall out of the case, I just didn't like the way those corners looked. I used it for a few months and gave it to a friend. A month later, she was complaining about the weight as well.
I have one of their journals still, and it's a work of art. But then again, I rarely hold it in use, so the weight's a non issue, and I never fold it completely back, so there's very little wear. I wouldn't consider their iPad cover; aside from the corner straps and the weight, their system for supplying a supposed typing position is just silly. All in all, to me it's very much a matter of form over function--but from what I've seen, I'm in the minority on that position.