I refer to it as 'the movie manga' because like the movie it's titled "The Adolescence of Utena" and that would be confusing. I haven't watched the entire movie, but a few differences I can note is that it doesn't have room for side characters. Or cars.
But more importantly: It's wonderful. Sensual without pandering, beautifully drawn and really something to think about. Watching the show or reading the other manga is required (because otherwise you'll have no idea what just hit you), but after that this reinterpretation is really recommended. It's less than 200 pages and really makes the most out of them, focussing on Utena and Anthy and how they see the world. If you want to understand Anthy better: pick it up. If you thought she was horrible: still pick it up, it's awesome.