Heads-up on the game, it's really one of the best games ever in my opinion!
I mean, I've played it for hours and I haven't finished the first part of the story arc simply because I enjoy too much traveling through the countryside, discovering new locations, enjoying the Sun's rise or fall, tracking the train on my horse, playing the bounty hunter, helping people in distress, etc.
The "secondary" missions are just as good as the principal plot, it really is a rich universe, there is always something to do or some landscapes to look at for their beauty.
It's also a lot of fun to catch some outlaws with your lasso, then go back to the sheriff while being tracked and shot at by his complices.
The mini games are fun too, poker in the saloon and stuff like that.
I also love all the random elements, like when you're on the road and a guy stops you and asks for help. Then you get off your horse and he tries to steal it from you or shoot you. It makes you paranoid because sometimes you tend to shoot innocent people in fear of them robbing you.
Anyway, great, great game, I highly recommend it!