I doubt this ...Although this may be correct theoretically, visually, I have personally seen both the FHD and the HD 42'' side by side ...I couldnt make out any difference visually between what the 2 sets were displaying ...This also happens to be the opinion shared by many people across various AV fora..
Maybe at higher dimensions like 50+ it may be an issue but at 42'', absolutely no issues ...
However, if your purpose is gaming, it may make a difference .
But for TV viewing or movies, i doubt. Just my 2 bits .
How far away were you standing and what was the video source?