I always get my ios devices with white bezels. Usually the silver, but the back doesnt matter as much to me, because i alwaysput my ipads, iphones & ipods in a case. I prefer the white bezel because it makes the screen really pop. I like that seperation. Plus the white is less reflective. I find the high reflectivity of the black bezel annoying. Especially in the sunlight where the screen is already reflective. The white bezel is leas distracting.
When it comes to macbooks tho, i do prefer the black/space grey over the silver. But with ios devices, the white bezels all the way.