Having only seen Frank Vincent in The Sopranos, I was interested in seeing him in a different role, even if the movie is basically the same genre. I was pleasantly surprised.
Of course, being a Mob film, there are all of the same stereotypes one finds in any such film. In real life, stereotyping is abhorrent, and leads to ridiculous assumptions, unfounded fears, and sometimes even violence. However, just like any other genre of film, there are going to be certain elements in common. High school/coming of age films are a prime example.
In this film, it was refreshing to see Vincent as a person with a heart, in spite of being a criminal. Through the development of the film, we realize that he wasn't a great parent, but he has learned from his mistakes with his family. One large motivation for the character is making amends with his remaining family members, and trying to distance them from his troubles.
The film noir feeling throughout was quite enjoyable. For some reviewers, it made it feel "slow," but I didn't find that. For me, the somewhat slower pace with the film noir feeling provided for a bit more character development than many films give. It could have gone a bit deeper, for my taste, but that doesn't detract from the film overall. The film noir elements also serves to heighten the tension between characters, good vs. bad, and the decisions/actions of the characters.
Overall, Chicago Overcoat is neither The Godfather, nor The Maltese Falcon. Drawing from both genres, the film may well become a cult favorite.