As someone who originally hated Kingdom of Heaven after seeing it in theaters but then shifting to loving film after the director's cut came out, I can confirm that the differences between the two versions are night and day. I always list the film as one of the prime examples of director's cuts improving theatrical releases (along with, of course, Blade Runner).
I would add American Gangster to that list.
(I'm in the minority on Prometheus, Covenant, and, yes, Robin Hood but I can live with that)
