If you like GTA, you will love RDR!

+ Long playing time (30-40 hrs.)
+ Many side quests (including challenges, foreign persons, etc.)
+ Interesting main quest / plot
+ Good control (Dead Eye, horse riding, ...)
(Have duels, honor and glory effect on the reaction of others) + believable game world
+ Lots of ways to raise funds, which are also interesting (breaking in, Five Fingers, horseshoes, Blackjack, Poker Dice, Poker, vigil, etc.)
+ Good balance of each weapon (genera) each other (useful weapons)

- Shadows and AA could be better
- Sometimes long bridle paths (which can shorten the good fast travel system / train)