I'm an extended version person. Once obtained, I don't ever watch the theatrical release. IMO, theatrical releases often leave out scenes that help explain other aspects of the film, or at least add to character development that helps us better understand the motivations of the characters presented in the film. This is usually done in order to meet some length of film concerns or requirements, and while I do understand they are trying to keep the audience interested throughout the film, or meet some theater timing requirements, these deleted scenes often leave us with questions, intentionally or not.........
One example that comes to mind is the 20+ yo old film "Boogie Nights" (Mark Wahlberg). I believe the theatrical release was in the 2.5 hour range, and some folks complained it was too long. I watched that release at the original Premiere, but had also seen a version that was 3+ hours before it was released (albeit with the editing timer in place, which I always find distracting), and I thought the longer version was much more entertaining, did a better job with the characters, and actually held my interest better. (Others associated with the film agreed.)
Jim