I have used both setups. I had a 3000w inverter off of a 3 bank RV deep cycle batteries and an isolator hooked to my HD alternator on my truck. Yes quiet, yes expensive ($1k), yes heavy, and yes a PITA to run the wiring. But start up the truck and it will run all day. My truck (06 F150) burns about 1.5 gallons per hour at idle. During my downsizing I an now running a Honda EU2000i inverter generator. Small, light, yes very quiet. Can't hear it over a vac or when running a DA. You need to hear one in person, videos do not do justice for how quiet they are. Still powers my steamer and extractor just fine. A gallon of gas will last all day. And get a Honda!! I bought an "other" brand for much less, returned it after 2 days when it started to sound like a freight train full of bolts coming off the tracks. They do cost more, but after having to reschedule then lose a customer because they didn't have power for me and I was out a generator -learned my lesson... don't cheap out
Mike