I read the book before I ever saw the John Wayne movie. The book is actually a bit darker (don't want to go into spoiler details.) It is a perfect Coen Brothers vehicle.
I *love* John Wayne (The Shootist! The Quiet Man! Stagecoach!), but let's face it, he was pretty much always just playing John Wayne.
I am also a Jeff Bridges fan from way, way back but I have to admit I was a bit surprised that he was chosen to portray Rooster Cogburn. However, I do know that Bridges has depth and range, and the Coen Brothers don't care how popular the original character was--they have their own creative vision. If there must be another adaptation of True Grit, the Coens are the right ones to do it. (Plus, I'll take Matt Damon over Glen Campbell any day of the week, and twice on Sundays.)