So Boston is basically just a massive slut. Great pickup skills, and generally has mostly one-night stands, or two or three “regular” partners. It’s mostly his ego, and possibly a self-destructive impulse that causes his conflict in his story. Plus some not-so-great friends, as it turns out, though I don’t think the series writers intended it that way.
Vegas on the other hand, is the first son of the leader in the “minor family” of a Thai mafia. He’s manipulative, 2-faced as it gets, excessively violent, sexually sadistic (extremely), borderline sociopathic. I say borderline, because he does have a conscience, buried very deep, and he has a pet hedgehog he treats better than people.
I’m pretty sure I wouldn’t want to necessarily know either of them in reality.