I'd like to know why people think white gets 'dirty' faster. The white surfaces are GLASS, just like before. No dirt accumulates on them. If they're thinking of the aluminum surface, nothing more than finger prints and smudges... simply wipe them off.
It's a no brainer IMO. If you don't like the look of bare metal shining through the black finish, get the white one. Who knows if Apple will even get the issue fixed.
The "dirty" issue with white iPhones, at least with my white 4S, is around the seams. After a year of use, with no case, my iPhone is starting to get black lines where dirt has worked it's way in around the home button as well as between the glass and plastic bezel.
“If you are neutral in situations of injustice, you have chosen the side of the oppressor. If an elephant has its foot on the tail of a mouse and you say that you are neutral, the mouse will not appreciate your neutrality.” Bishop Desmond Tutu