Something new, and yet similar. You will have fun.
First, the graphics of the game are... good enough. Not the best thing I have seen by far, but they suit the game. Also, you may find that the world of Red Dead Redemption seem like a great empty desert, which is a little annoying until you reach the more forested areas of the world.
Now, the gameplay! This part is great. The game handles very well, and there is a lot to do besides just story missions and side missions. You can hunt, search for treasure, play poker, duel and many other activities. This adds a more realistic feel to the wild wild west setting. The story of the game is very satisfying, especially when you near the ending. I don't want to spoil the ending... but it will have an effect on you.
The multiplayer mode is great! Very good. The free roam is fun, regardless if you are playing with friends or strangers, and the game modes are equally entertaining. There is also a "levelling" system in the multiplayer which makes you want to get better and better to get the rewards.
Overall, I enjoyed the game. There may be a few things that bug me, but I think this is the best rockstar game to date.