I think the Apple leather case is absolutely beautiful and sleek and does the best job of showcasing this gorgeous phone.
However, the bottom of the phone isn't covered and the case is thin so I'm not quite sure how shock absorbent it is supposed to be or how well it will protect against drops (although I've read some posts that mention a few drops without damage to the phone) and if the phone happens to hit on the bottom, then the phone is bound to get nicks and scratches and who knows what could happen to the screen. I normally never worry about dropping my phones because mine are usually attached to lanyards but since there is no bottom on this case, there are also no cutouts to attach the lanyard loop.
Lastly, many find that the leather case is so sleek that it can be quite slippery at times which could be a problem with the new bigger phones since we are all still getting used to holding on to them.
Some people opt for the Apple silicone case because it offers the same sleek look but with a grippier feel.
It just really depends on your job and daily activities and if you plan to use it as your main case. Then you can decide if the case is for you. I suggest looking at one in person if you haven't already and seeing if the case feels right in your hand.
I know I won't be using my leather case very much except probably for dressier occasions where my phone would be safely tucked away in my purse anyway. It will also be backup for my husband in case anything happens to his leather case.