I have many cousins and friends who have seen it. They are all ranchers, raising cattle, and very into anything western. Quite a few of them are collectors of western memorabilia. Their knowledge is quite astounding... the can look a horse's bit and tell you within maybe 5 years when it was made, where, and sometimes by whom.
My point is.. they've been talking about that movie and are giving high praise for it's authenticity.... yes, they've caught a few mistakes, but overall they are saying it's one of the most authentic depictions of the old west in the history of movies.
I haven't heard any of them discuss the actually story yet.