I guess if you are in the dark, black is less "distracting", but I wouldn't say white is distracting really.
The only thing that bothers me is that the part of the screen that doesn't contain pixels is noticeable in white devices, while it is not on black ones, since it's entirely black already. So because of this you have white, then a black rectangle, then whatever is on screen.
The same goes for the light sensor, it's invisible in the black iPhone, not so much on the white one

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The black one kind of disappears easier, but that said, these are not devices you want to hide. White is more catchy, I love it. Also the screen looks nicer, I find the contrast with white to be nicer, and with iOS7 specially, I just love the color combination. With the black one iOS7 looks just...meh to me.
Anyway pick the one you like the most, I have a white iPhone 5, coming from an black iPhone 4S, and the user experience when it comes to consuming content is exactly the same.
I had a black iPad 3 that I sold a long time ago; I'm taking the iPad Mini with retina display in white this time around. That mini looks gorgeous in white.