We did have a whole home unit, when we lived in Florida. Got spoiled and hate the manual portable unit that we have now. Worse up here in Maine using a manual during a winter storm. We are out in the country here and would need to us LP. But I see that LP will give you more amperage than NG, for the same unit.
Do they at least kill the main breaker to the panel (to isolate from the grid) when they do that?
Today's whole home generators have automatic switch over from utility to generator power. If your utility power is down for say 10 seconds, it will turn the generator on. There are also switches called smart switches that allow you to use a smaller generator to power your home. It just will not allow to many high amperage units to run at the same time. Example: Your electric stove will not turn on if your clothes dryer is running. It will wait for the dryer to shut off, then you can use the stove.