Very cool movie.
The backbone of the film are the 3 male leads: Russell Crowe, Christian Bale and little-known perennial scene stealer Ben Foster (as Charlie Prince). They look and sound great and the inertia of the performances drives the movie. The atmosphere of the film's world in general is well crafted. There's an abundance of 70s porn star vagina mouth facial hair, lots of mutton chops and mustaches and so forth. Everyone is appropriately dirty and sunburnt, while somehow still managing to look cool. The peripheral characters are equally well acted and colorfully brutal, fleshing out the film's impression of the Old West as a harsh and rugged place where the weak die fast. Peter Fonda (I didn't recognize him at all in this role) is especially good as a tough Pinkerton bounty hunter.
There's plenty of action, some of it quite gory, and also a surprising amount of character depth (or maybe not surprising given the actors). There are a few cheesy moments, but the overall quality of the film easily cancels them out. Also be prepared for some subtly humorous lines. Russell Crowe is powerfully charismatic as super outlaw Ben Wade, a Hannibal Lecter-type villain who is effortlessly violent and always in control, even in captivity. You wait for his downfall but root for him to win.
I don't know what it is about this era, but outlaws and cowboys just look cool.
The avalanche of B-grade Westerns that Hollywood churned out for most of the 1930s, 40s and 50s thoroughly oversaturated the market and ultimately the public turned away from them. With the Clint Eastwood spaghetti westerns and newer takes on the genre, like Tombstone and the 3:10 To Yuma, we know that the Western can be a vehicle for some very entertaining filmmaking. Now, we just have to wait and see what The assassination of Jesse James is going to bring to the table.