Miniaturization and portable devices have reshaped the electronic device landscape, emphasizing the importance of high performance while maintaining energy efficiency to ensure long battery life. FinFET and Tunnel-FET technologies have emerged as attractive alternatives to overcome the limitations of supply voltage scaling for ultra-low power applications. This work compares the performance of 10 nm FinFET-and TFET-based digital circuits from basic logic gates up to an 8k gates low-power microprocessor. When compared with their FinFET-based counterparts, the TFET-based logic gates have lower leakage power when operated below 300 mV, show higher input capacitance, and exhibit a reduced propagation delay under different fan-in and fan-out conditions. Our comparative study was extended to the synthesis of an MSP-430 microprocessor through standard cell libraries built particularly for this work. It is demonstrated that the TFET-based synthesized circuits operating at ultra-low voltages achieve a higher performance in terms of speed at the cost of increased power consumption. When the speed requirements are relaxed, the TFET-based designs are the most energy-efficient alternative. It is concluded that the TFET is an optimal solution for ultra-low voltage design.