Finally saw it in cinema last night.
Almost a full house for a western movie, I had not experienced this since the Seventies and the re-release of Once Upon a Time in the West (I haven't seen Dances with Wolves in cinema)
I noticed that Leone's meta-western was mentioned in relation to this one and yes, there are similarities (in framework and design), but I didn't notice any meta level (in other words: I don't think this western is a comment on westerns). Other directors who came to mind were Malick and Jarmusch (Dead Man, the dream sequences), while the opening scene reminded me of Scott's Gladiator (rather than Peckinpah).
I having mixed feelings about the movie itself: Great look, murky content. As more often, the director seems to overstretch the 'meaning' of his movie: it clearly is supposed to say something, but ideas are only hinted at, never properly developed. Visually it's of course stunning, the bear attack is a horrifying highlight, but some things were better done in the Richard Harris' movie Man in the Wilderness (the recovery from the wounds for example).
I'll probably write more about the movie in the next few days;