Two very different things.
Solar power is a passive charging system which works only when it gets enough energy from the sun. At night, camped in the trees, even a cloudy day, solar will not do any good or not much good.
The genny provides power for a much higher rate of charge than solar, whatever your onboard charger produces, plus while you are charging you can use most of your 110AC devices.
For dry camping battery bank capacity is king. On a nice day solar will be charging that battery bank without you being there.
Having an onboard inverter is good to have with either solar or genny. Solar puts power back into the battery bank as the inverter takes it out. With a good sized battery bank & a genny, there is no need to run the genny for small loads like the TV or all those device chargers.