The movie soundtrack has a much larger orchestra so the orchestrations have been "beefed" up. Gone are the full Overture (never used in the show but on the OCR), In Old Bavaria, the reprise of Opening night, and Where Did We go Right. In addition I Wanna Be a Producer, Along Came Bially and Springtime for Hitler are shortened.
On balance, they have added a short track called "You'll find your happiness in Rio" (which is a nothing), a strange version of Guten Tag Hop-Clop and a new song called There's Nothing Like a Show on Broadway.
Packaging: The Broadway cast has a synopsis and all the lyrics plus pictures. The soundtrack has more pictures but hardly any notes and no lyrics.
Generally the cast album plays better and you get more of a sense of the story.
Cast albums are NOT "soundtracks."
Live theatre does not use a "soundtrack." If it did, it wouldn't be live theatre!
I host a weekly one-hour radio program featuring cast album selections as well as songs by cabaret, jazz and theatre artists. The program, FRONT ROW CENTRE is heard Sundays 9 to 10 am and also Saturdays from 8 to 9 am (eastern times) on www.proudfm.com