The guys over iSpazio have made a usful videos regarding white iPhone 4 to test out a few of the areas of concern users have had with the black iPhone 4 devices, they tested
both the proximity sensor performance and signal loss caused by “death grip” in black devices.
White Phone 4 exhibits excellent proximity sensor performance:
the white iPhone 4 exhibits excellent proximity sensor performance, responding immediately to turn off the device’s display when covered but then also keeping the display off until a finger or head is a “relatively large distance” away. The black iPhone 4s initially exhibited problems with displays coming back on while on phone calls, resulting in unintentional touch input. The issue was largely fixed in an iOS update, but it is reassuring to see that the white models exhibit solid performance from the get-go.
White iPhone 4 singal has been improved compared with black iPhone 4 :
iSpazio also tested the “death grip”, attempting to generate signal loss by covering portions of the stainless steel band that serves as the antenna for the device. As with black iPhone 4s equipped with iOS versions released since Apple addressed early issues, the white iPhone 4 exhibits a slight drop in signal strength, but the drop does not appear to have a significant effect on connectivity.
Finally I have to say it looking that white iPhone 4 doing well than black iPhone 4, may be Apple has changed the material used in black devices. Thanks Apple