booth for sure. you get an overview of the opposing defensive schemes. makes for better play calling
I personally think the booth is best. You simply can't see everything going on from the sideline. From the booth you can see everything, point things out, and make adjustments. As far as getting in players faces, that is the job of the position coaches, and head coach. The coordinators main role is to execute the game plan, call the offense/defense, and make adjustments as necessary.