Mafia 3 has one of the strongest starts I can remember in a video game. Has an absolutely 10/10 character performance and style of story telling, via a documentary-like ongoing interview with the characters from the game, remembering what happened with Lincoln. The characters are deep and feel meaningful, with a real impact on the story. Having some well written dialogue. The world feels very accurate and well done, creating a very good impression on how it must've felt during that time, specially with the hard reality, involving racism and the bad people around the world.
What holds the game from being a 5/5 are some technical issues, making me have to reload the last checkpoint for about 4-5 times during the full 20h main story. As well as some repetitive structure of missions, that I imagine can get even worst if you go out and do all side quests before going forward with the main story. So I would recommend for people to just do the main stuff first.
I still higly recommend Mafia 3 for open-world fans. Specially now that you can easily get in some steam sale.