Depends on so many factors. Screen size and viewing distance go without question and then there is, very simply, the devices being used - a Denon DVD-2500BT player is going to make a much better job of the Blu-Ray than an LG-BD300 for example, so how do you rate 10. In the same way, a £2,500 Pioneer TV will more than likely upscale an SD source much better than a £30 DVD player.