I normally don't write reviews, but I figured it's never a bad time to start.
I'll jump right into it.
I have never before gotten a case for my iPhone. Cases add bulk, take away from the aesthetic of the phone, and are just another "thing" to keep track of. But when I heard about the "leather case":http://store.apple.com/us/product/MF041LL/A/iphone-5s-case-brown that Apple created specifically for the iPhone 5s, I thought that it would be the end of my no-case journey.
It came a couple of days ago in the mail. I ordered from Best Buy online. The cases come in 6 color choices--brown, beige, black, yellow, blue, and red. I went with black, since it was the only one that could really go with space gray. Not to mention, I'd read a bunch of reviews that said the other colors (especially the brighter ones) were prone to picking up dirt quickly.
The case looks and feels great in the hand. The leather is no frills and simple. It's not the sort of leather you'd see on a cowboy boot, but supposedly it's real. There is a stamped Apple logo on the back. It looks pretty cool, and gives it more authenticity, I guess.
Putting the case on is quite easy. It really is fitted quite well to the form of the phone. Sort of expected for a case, especially if you're also the manufacturer of the phone itself, but I suppose it's still a good thing.
As for bulkiness, it didn't add much, but it _was_ enough to be noticeable. In terms of weight and form factor, the iPhone 5s with the leather case "felt" like my 4S in the hand. This isn't necessarily a bad thing (some people might like that), but it's not totally for me.
The biggest problems I have with the case are more functional and less visual.
1. The leather cover over the power button is a bit too stiff. One should not have to struggle when pressing the power button.
2. The volume buttons are not covered like the power button is, but they're still quite hard to reach. It's not impossible by any means, but it's just hard enough to be annoying.
Given that I wasn't blown away by the look and feel and the usability problems that it has, I decided to return it. I think I'm still in the market for a case, just not the Apple one.