One thing I just discovered on these DLC finishes. If you touch the case with your finger, the oils on your skin leaves a slightly dark mark. In the close up photos of my 026 and others, you can see a bit of a "splotchy" appearance. What you are seeing is not variation in the DLC color, it is oil from finger prints. I understand that you can apply gun oil, or high spf sunscreen to the DLC finish to remove the prints, but I believe that will permanently darked the finish. The other option is using a nice pencil eraser (like the ones on mechanical pencils). The eraser completely removes the dark spots and turns the whole case lighter, to its original, no finger oil finish.
The smudges don't really bug me, but if they bug you, and you don't want to risk turning your finish darker by using sunscreen or gun oil, just get your pencil eraser out!