I considered a whole house generator, but opted to go solar instead...because it offers me payback during normal conditions (we haven't had an electric bill in 12 years) and had a 30% federal tax credit, where as a generator is simply a money pit in financial terms.
During grid down conditions, I walk out in the garage and flip a 100amp transfer switch to our solar which either delivers power from the panels or the battery bank, depending on sun conditions.
Nice thing about a battery bank is if you need a small amount of power in the middle of the night for example, you aren't running a generator to supply it.
If we got many extended days, and no sun, I'll use a small generator for a few hours to charge the battery bank.