said by Bob4:
Some folks here have generators with inverter outputs. They say they're much quieter, are more efficient, and produce cleaner power.
The problem with inverter generators... when the inverter fails, the generator is completely useless and the repair is usually very costly (usually the entire inverter module needs replaced). Not as much of a problem with good quality units that have a good warranty, but it's something to beware of with the cheaper inverter units.
Also, "cleaner power" is highly debatable. A good quality non-inverter generator can have a very clean output waveform and tight voltage and frequency regulation. Maybe if you're comparing a decent inverter unit with a cheap-ass non-inverter, then yes the inverter will probably have better quality power, and that's assuming the inverter isn't one of those "modified sine wave" units.
The main advantage of an inverter setup is that it is the inverter that produces the output AC waveform and thus the inverter sets the frequency, this means the output frequency is independent of engine speed. Therefore, the engine speed can be adjusted depending on the load in order to improve efficiency and reduce noise during low or medium loading conditions. In contrast, since a non-inverter generator's output frequency is dependent on engine speed, the engine must run at a constant speed all the time.