Hi,
An inverter generator produces high frequency and high voltage DC electricity and then "changes" it to AC power @ 60 hertz. The biggest advantage is that the motor does not need to run at one speed so it may run much slower under low loads--saving both fuel and lowering the noise. The inverter part may rival or even be better than the quality of power from a shore line.
I prefer to use solar power and I get my ac power from an inverter connected to my battery bank.
Yamaha, Honda and Champion all seem to make reliable inverter generators. There are lots of Chinese "knock offs" the best of which seems to be Kipor. As for the rest "buyer beware".