Load-following fuel cell systems depend on control of reactant flow and regulation of DC bus voltage during load (current) drawn from them. To this end, we model and analyze the dynamics of a fuel cell system equipped with a compressor and a DC-DC converter. We then employ model-based control techniques to tune two separate controllers for the compressor and the converter. We demonstrate that the lack of communication and coordination between the two controllers entails a severe tradeoff in achieving the stack and power output objectives. A coordinated controller is finally designed that manages the air and the electron flow control in an optimal way. Our results could be used as a benchmark of achievable fuel cell performance without hybridization