I have the Product Red case and like it so well that I ordered the blue as well. Since then, I've had second thoughts and will most likely exchange the blue for a black case instead. Unfortunately aniline leather does tend to get dirty and is more difficult to clean than other leathers. With my red case, I immediately conditioned the leather and then sprayed it with leather stain protector. I'm hoping this will protect it from stains and dirt.
I just picked brown based on my past experience with brown leather. While I try not to touch it with greasy hands, for the most part I just let it be and it developed a nice patina over time.