The USB powered I find very handy, my device (LG) must be connected to the USB port when you turn off normally, so the lighting is always automatically when the device is switched on.
Only a USB port Since I have both devices available (which is in each case used for recording / playback), was charged with a USB Y-cable (Y Delock port USB 3.0 A to 2x USB 3.0 cable A; 0, 3m) and an adapter USB socket / socket (Wentronic USB adapter; A Female to A-Female) a power supply for the backlight up, which still allows a data connection.
A star deduction there, because the existing on / off switch is a rotary switch with no possibility of brightness regulator Lung mE a weak point. Here is a real dimming option, the fifth star would have been.
The light color is at or below 2700K, the light appears white with a slight blue tint, but I did not feel uncomfortable. The illumination is uniform (a tip: the strips attach not too close to the outer edge devices, then the light is unobtrusive).
Overall a good value for money and a relaxing of the ophthalmic solution with a neutral light color for TVs up to 42 ".