After about 10 minutes of using the phone, the buttons at the bottom are mastered and them lighting up is completely unnecessary, so I don't think that should be of much concern.
I have taken a few pictures with my White version and I have noticed no artifacts related to using it. That would be a big design flaw on Samsung's part if it actually caused some issue.
At the end of the day, all you really need to worry about is the front of the phone and what color you want it as you can replace the back with a wide range of colors.
I like the white simply because it will go with more colors than the grey would, but that is just my preference.
