An advantage of unipolar over bipolar inverters is reduced switching losses. For an inverter to work, it has to draw electricity. This power supply is the solar panel or windmill itself. Unipolar inverters have been demonstrated to draw less power than bipolar by research conducted at the University of Southern Queensland. To put this into hard numbers, suppose a solar panel is putting out 100 volts. A bipolar inverter draws 10 volts of power, making 90 volts available for the load. A unipolar inverter may only draw 5 volts of power, making 95 volts available to the load. Therefore, they are more efficient than bipolar inverters.
A unipolar inverter produces less EMI, or Electromagnetic Interference, than a bipolar inverter. What this means is that less electrical noise is generated by a unipolar inverter. EMI is transmitted in much the same way as radio waves. This noise is often heard as "AC hum" coming from speakers of a home stereo system. If a bipolar inverter is used, more metallic sheathing is needed around the inverter to catch the EMI waves radiating out.
Graphs developed at the University of Queensland depict that a unipolar inverter has an output that is closer to a pure sine wave than a bipolar inverter. For small electronic appliances, this is significant. A small power supply is designed to accept a pure sine wave. Feeding it a triangular-shaped wave is hard on the supply since it has to "clamp and hold" various voltage levels. The end result is that AC hum is sometimes heard through loudspeakers, and the life of the supply is reduced due to a strain of the components, which is very much akin to over revving a car engine for a very long time.