Well, I’ve watched both versions of one of my favorite books, All the King’s Men. The newer one is of course prettier and more stylized, but I would say the 1949 version is more faithful to the book.
Further what is at stake for the characters is more clearly apparent in the 1949 version. You can see how goodie-two-shoes Willie Stark became the corrupt and philandering man he became. Further, the pain caused by his philandering, both to his wife, Lucy, and to his personal assistant, Sadie, who he first cheated with, is much more apparent. True, we don’t get to see Stark’s dalliance with the stripper on skates as we do in the 2006 version, but we do get to see Sadie’s grief over being rejected and replaced by Willie on account of her looks.
Overall I would say the 1949 version gets the story right. It does not just focus on Willie and Jack’s relationship (the point of view character and Willie’s muckraker), but on the myriad of emotions and drives of all the characters.
The only superiorities of the 2006 edition are the foreshadowing of violence by “sugar boy,” Willie’s hired gun, the inclusion of Jack’s question about Willie winking at him when they first meet, and highlighting the Judge’s affinity for model catapults and other ancient projectile weapons.