the biggest difference between these is going to be what you are going to hear out of them or maybe i should say what you don't hear out of them. for the most part when they make a dvd they do not have the extra space to put the best sound in so that is what is left out. the blu ray disk has so much extra room that they can but in the best sound they have out there. voices sound that much better, instruments sound alive, explosions feel like you were in one, breaking glass sounds like it really should, and rain sounds like it would right outside you window. this is why blu ray can give you the best sound out there and use many different kinds of sound.