Originally Posted by Riocaz
but do sacrifice power...
Not really. Finger touch screens are not generally used the same way as stylus screens are. The only time the stylus screen impacts power usage is when you're continuously drawing on it. You don't really do that with a finger screen.
The power difference doesn't seem to have much to do with the layer being above or below the screen, or necessarily whether it's finger or stylus. The difference is most likely due to the continuous usage pattern of the touch layer.