@Wagwan piffting23 R* in general just has a fantastic rouges gallery. As much as I love to hate Micah, I must give this one to Ross; He just has such a stage presence, and steals the show whenever he's on screen. He has so many iconic moments; his exchange with John about Dutch "admiring the flowers" may just be my favorite line in the entire Red Dead series.
Both of these characters have fantastic voice actors as well. Peter Blomquist does an amazing job, really selling the role. He also seems like a really great, funny guy in real life. I don't know too much about Jim Bentley, but he also does an amazing job, really bringing a charismatic flair to Ross as a character.