If you like games that are all action, bang bang shoot shoot, you probably won't like rdr2. Every time you loot someone there's an animation that lasts a few seconds. All sorts of stuff like that just adds up.
It is very beautiful to look at, a real work of art, the story is pretty good, but the characters are great, Arthur Morgan is quite dry and sarcastic, probably the most realised game character I've seen, there will be a few moments you get a lump in your throat in the closing chapters.
You could bash through it in 40 hours or so, the gameplay is GTA with horses and less firepower. Or you could spend a year on it hunting mooses and playing poker.