The diode version loses two voltage drops from peak-to-peak voltage. The MOSFETS turn on fully and only lose a threshold voltage around the midpoint. Useful for driving a resistive or inductive load only. Crank up the load capacitor to 1uf and see the mosfet rectifier conduct in both directions, whereas the diode rectifier doesn't. Reduce the resistor, thus increasing the load, and see the effect on the output waveforms.
