Harvesting energy from ambient vibrations in order to power autonomous sensors is a challenging issue. The aim of this work is to compare the power output from an innovative wideband fractal-inspired piezoelectric converter to that from a traditional multicantilever piezoelectric energy converter. In a given frequency range, the converters are tuned on the same eigenfrequencies. The effect of the input acceleration and of the resistive load applied to the converters is investigated experimentally for each of the three eigenfrequencies in the range between 0 and 120 Hz. The fractal-inspired converter exhibits a significantly higher specific output power at the first and third of the eigenfrequencies investigated.