Honda seems to be rated exactly the same as the Yamaha and 2-300 dollars more expensive, although the Honda name might be worth it. My battery charger requires 535 watts input and using it alone would seem to be within the capabilities of either unit. Charging off the inverter would certainly reduce the load further although at the expense of a longer run time. Really wouldn't have much to use it on other than battery charging (and about 45 other things I can think of if I thought to keep it in the back of my truck!)
I suspect I'm missing your point Cam. I know-not unusual!