Do any of you have issues with your iPhone 4 brightness? I've always left my brightness control on auto, but more often than not, the screen is either way too dim for the lighting that I'm in or the brightness is way behind in adjusting itself (often up to 5 minutes after I've moved into a darker or lighter environment). Could it be that iPhone 4 is just designed to auto-adjust it's brightness leaning more toward the dimmer side in an effort to conserve battery life, or could this actually be a problem? I've had to turn the auto brightness off entirely and adjust it to my own liking because it doesn't seem to be doing it's job. Or it's extremely slow to do it's job. Often times it doesn't adjust at all after changing to a lighter/darker environment. Kind of a frustrating issue ...any suggestions or feedback would be appreciated. Thank you!