Yes, the quality inverter generators are substantially more expensive than a non-inverter counterpart.
There are benefits to the higher cost design. Based on my experience with a Honda EU7000is (and several other inverter generators in the Honda lineup) the main benefits are:
• Clean power.
As the AC output is created by a DC/AC inverter circuit, producing a pure sine wave of very high stability and very low distortion is possible.
Appliances powered off an inverter generator work as well as when powered from a battery inverter (and better than grid power in many cases.)
AC Input to a battery inverter is always accepted across the generator’s full power range. I never have problems with the input being refused due to malformed AC.
• Fuel economy.
The Honda employs fuel injection and electronic engine speed control (Eco Throttle). At medium to low power outputs, the Eco setting sips fuel at very low rates. This is helpful for reducing emissions as well.
• Quiet running.
The Honda is an enclosed chassis design. It runs quieter than any other portable generator around. The variable engine control helps with this as well. Even running “full gas”, I can stand next to the generator and have a conversation.
Open chassis designs, of course, will be louder unless installed in a sound shroud.
Clean power, fuel economy, and quiet operation are the 3 main reasons I have run nothing but inverter generators for over a decade at our off-grid home.
Is an inverter generator strictly needed for the GX in question? Probably not, if the non-inverter model is low enough in distortion and high enough in waveform stability.
Will it benefit from one? In most all cases, yes.
I know folks who have done LPG conversions, but the setup has issues, so I consider the Honda to be petrol only.
The features mentioned is what I’d look for in any inverter generator.