When using my iPhone in a dark enviroment and using a rather low backlighting there is a darker spot on the upper right part of the screen. When a raise the backlight it's not that visible anymore. It's kinda bothering me, so does this warrant a return? On the other hand I'm very satisfied with my unit, no faulty pixels, no cracked case... I'm also afraid that they might not exchange it as soon as I got a more serious "problem"