The ARIES team has assessed the power-plant attractiveness of the following five tokamak physics regimes: 1) steady state, first stability regime; 2) pulsed, first stability regime; 3) steady state, second stability regime; 4) steady state, reversed shear; and 5) steady state, low aspect ratio. Cost-based systems analysis of these five tokamak physics regimes suggests that an electric power plant based upon a reversed-shear tokamak is significantly more economical than one based on any of the other four physics regimes. Details of this comparative systems analysis are described herein.