I believe it's better. Most users won't notice any difference, but some do which use the HDMI connection from graphics card to monitor in a 16:9 format. Sometimes an inch border or so may appear if scaling is not adjusted correctly. Easy fix though.
I can enable and un-enable GPU scaling just fine and I don't have any black bars of any kind. The only problem I have is a slight flicker of my monitors when GPU scaling is enabled and it only happens when closing screen on a youtube video. Strange....
I think I've solved the flicker problem on monitors, whether gpu scaling is enabled or not, while watching/switching youtube videos. Right click the youtube video, select settings and the hardware acceleration box pops up, untick box....refresh or close/open and flicker is gone...it was driving me nuts. All good now.
Im running duel fire pro 7800's and noticed explorer causing interruptions to the graphics. I found in the process explorer by sys-internals under the system box you can select which gpu engine to use. It appears only gpu 1 is selected, which is also the gpu that handles the most display processing. By moving the selected engines over to 4,5,6 it seems to have taken the strain from gpu 1 processor.