I did a quick search. Those are made in China. The db rating on them seems low until you look at Yamaha or Honda, which are twice as quiet. How big of a generator are you looking at?
My choice would be propane, with an auto start feature that doesn't depend on you being there to fire it up. You'll also need a automatic cut-off switch so you don't backfeed to the grid and fry a utility worker.
The propane sure seems to be the way to. I think I'm looking for something big enough to start up the geothermal, run the well pump, a refrigerator/icebox, one chest freezer and another 200 watts for the two fish tanks. We can definitely do without the TV and the computers for a while if we had to. Lights are no big deal either.
I'm going to call the manufacturer of my geothermal and my well driller to get the watts and start up watts on those. The other stuff is easy.
