The 5.1 track that was the only option on the DVDs doesn't sound like a true discrete mix to me, although I'll admit I haven't listened too closely to it. It has some moderate hiss reduction.
The mono track on the 1998 Warner LaserDisc sounds wonderful. No hiss reduction, no strange EQ, just a faithful representation of the theatrical mix.
The Criterion blu-ray sounds rolled off, though I wouldn't say it sounds objectively bad since the underlying magnetic track sounded so good in the first place. The Warner blu-ray is perhaps a bit better than the Criterion, but it's essentially the same -- more muffled and less immediate than the LaserDisc. Sissy Spacek's narration, especially, sounds hollow on the blu-rays.
