I watch both on my Oppo and since the video upsampling in the BDP 83 is very good for converting DVD to 1080p I will sometimes buy a movie used on DVD instead of blue ray because it is so much cheaper and the movie is either older or would not really benefit having it in blue ray like some of the action films or something with a awesome sound track or great video. I have watched some of my older DVD's on my Oppo and they look quite good when being upsampled to my Samsung LED tv. But movies like Avatar and the like really do benefit both audio and video wise by having the blue ray copy if you have the equipment that can really bring out what the format has to offer.