Wouldn't using DPLII equate to watching a movie in DPLII and SACD equate to watching that movie in Dolby Digital? You get some sound in DPLII for movies, but DD is the superior format.
I agree that it may vary from disc to disc, however I would be suprised to hear a lot of what I heard on the Dark Side of the Moon SACD in standard CD with DPLII turned on. Then again, with classical music that is likely not created the same way this disc was for SACD (DSOTM in SACD seems to be designed to use the surrounds, where I can see classical just using them as ambience) I can see where it would not matter as much.
