Single player is amazing and worth every penny, online can be fun with friends but.
Multiplayer can be fun but you really need a group of friends to play with, otherwise you're usually going to get spawn camped in free roam by some guy on horseback shooting at you from behind, or you get stomped in gang matches by groups of people who are playing with friends.
The stories ending was very much a curve ball and most if not all missions keep you wanting to play to get to the next mission and unravel the story even more. The graphics are impressive as well considering how large a scale Red Dead is, the physics and NPC interaction are great and very similar to the GTA series, which isn't a bad thing at all.
My only real gripe about this game is the multiplayer, again most of the time in free roam it's people shooting at you constantly for no reason other than to shoot at you and piss you off.