This work reports an evaluation of speed, energy consumption, leakage power, and silicon area tradeoffs of three different transistors topologies for C-elements, basic devices for building asynchronous circuits. The evaluation considers the devices operating under supply voltages that vary from nominal IV to 0.05V. Analog simulations provide precise measurements and the obtained results identify the lowest voltage at which each C-element operates correctly. Results suggest that operating at near-threshold voltages provides the best speed-energy and speed-leakage efficiencies. Also, they point the van Berkel topology as the most suited C-element implementation for low voltage operation, as it presents lower power and energy figures as well as higher speed, regardless of the supply voltage.