I own a few Superbit DVDs, although Das Boot is not among them. Greater care seems to have been taken with picture and sound on these discs. Probably the most notable difference is the general inclusion of DTS soundtrack on the Superbit discs. I haven't compared the picture quality on my current set-up with standard definition discs.
With the advent of HD, Superbit DVDs kinda died off. For a while you could pick up these titles for ten bucks or so. Not a bad deal. If I remember correctly the titles I have are: "Lawrence of Arabia," "Spiderman," "From Here to Eternity," "Punch Drunk Love," "The Patriot," "Underworld," and "Adaptation."
