There is more to it than just multi-channel. Because of dynamic range limitation on a CD, studios are using dynamic compression to logarithmically reduce the highest peaks without having to reduce low levels. At this point, what you listen to becomes very important. For rock and other nearly-always-at-full-volume music, the difference would be more negligeable. For classical, the difference is HUGE. An orchestra starts sounding like an orchestra and you get the full benefits of dynamics. I don't own any SACDs, but I have about 25 DVD-Audios.
