I thought the DVDs looked good but the blu-rays are way better. Better depth of field, color saturation, definition, etc.
I really don't want to sound too nitpicky but the BD feature talking about the remastering process has some visual demonstrations that hint, IMHO, that contrast was pimped to add an artificial punch to the otherwise mild and softer overall original presentation.
Fortunately this doesn't get close to the mess that is the Special Edition of Star Wars,
but its something to be considered, IMHO.