I read many comments at Apple site that silicone cases attrect dust, lint and fibers...
so I also wonder what color option looks good for silver iphone, how's the leather?
And leather cases attract dents and scratches.
So it's really a matter of personnal preferences.
I much more prefer wipping off some lint on my silicone case than dealing with dents and scratches on my leather case.
Silicone holds better, leather looks more professionnal (personnal opinion, here).
They both have a wide variety of colors. I know I love contrast so I put like a red or pink silicone case on my space gray 6s Plus and a black leather case on my silver 6s.