I always listen in DTS now, when avaliable. I was A-B testing for a while and on some DVDs, DD sounded about the same. But on most discs the DTS track won out, and never lost. I think the major difference, to my ears, is that at times in the DD tracks you can point directly to where the speakers are, and in DTS the sound seems to fill the gaps in between. It's as if you are immersed or surrounded with the audio seemingly coming more from the sides, rear, and even above. Although, I have to admit, on movies like the new STAR WARS, the DD tracks are very good. DTS is not available on these.
Sonny