DTS can be beneficial for some films due to the higher bitrate, but I usually prefer to watch films in their original release format. If it was a Dolby release then I stick with that track unless the other is a preferred option by the people involved etc.
The difference can be heard on some films: Tomorrow Never Dies was impressive in its Dolby mix. (like it was in the theater-okay movie, great sound mix) I switched over to the DTS just out of curiosity and was blown away.
Then again, I'm talking about standard and not HD or lossless.
The only way I can see DTS for Star Wars is using the 1997 DTS mix for the Special Edition and a brand new DTS 70mm mix (like the one created for the Vertigo restoration).