i read the book first, i think you will like the movie more if you do because it delivers on some of the amazing aspects of the book, but then again leaves a TON out and kinda changes the overall narrative of the story.
if you didnt read the book i think it just seems a bit odd, and it dosent do justice to some of the more ‘deep’ themes that the book really digs into, most notably in the 2 most futuristic settings. cloud atlas could have easily been 2-3-4 seperate movies.
but i highly recommend the book, it was great.