I like Sergeant York principally because of Cooper, but it's not the only factor; I think it's well written, acted and directed, I love Steiner's score. In short, I'm as entertained now as I was when I first saw the film maybe 40 plus years ago, and the basic reasons haven't changed much...
I've loved Sergent York since I was a child, and the foremost reason is simple - Coop. And I'm another that couldn't give a hoot about whether a movie is historically accurate or not.