Interestingly enough, I looked at the "Mad Men" portraits and immediately thought: "mug shots".
The lighting, subject position and camera position really tend to flatten the subjects. There is very little three dimensional modeling. That may be something you want.
The appearance of the fairly hard shadow immediately adjacent to the subjects' heads may appeal to you, or may irritate you. That is up to you.
The two factors together may be more suited to people who already photograph well (TV stars) than some others.