I have had my black bumper since launch and today I got my white bumper. There is a HUGE difference. The sides of the black bumper are made of rubber so it creates friction against the surface it is on. The white bumper seems to be all plastic and SLICK. I almost dropped my phone today because of the white bumper!! In my opinion the construction of the black bumper is FAR superior to the white. How about the other colors? Has anyone compared, orange, blue, etc to the black bumper? Any official word from Apple on which bumpers are made from what?