It depends on your display and the players and maybe the cables as well. Some say it's significant and some say it's slightly different. I will post again after I receive my upconversion player this Friday.
Depends on the player. Just read a review on Sound and Audio Mag. They revied the samnsung the tosiba 5980 and the Panasonic. the samsung and toshibas got a so-so review saying that the video so-so the mag award went to the panasonic. stated that the video did improve. I am looking into the LG LDA-511 trying to find some reviews on it.