Cheap generators don't have a good regulator in them to give a 60 hz sine wave and the govenor in them sometimes doesn't hold a steady speed and the output varies.
Computer (Esp laptop) power supplies are pretty flexable when it comes to power. They conver it to DC for the computer anyway. So I'm not sure I would use that as an indicator of the quality of your generator.
I would think the Honda is probably pretty good quality. If you have access to an O-scope you could check the outoput (voltage and HZ). You could also check it with a Multi meter but you wouldn't be able to see the quality of the sine wave. Remember to vary the load when you are checking it.
So the company probably makes a blanket statement since they cannot predict the quality of generator.
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