The hardware store sells portable generators. I install whole-home standby generators. Here is what the comparison actually looks like when you are standing in your driveway at 2am in a storm.
The portable generator
You have to start it manually. You have to connect it manually, which means either an extension cord running through a window or a transfer switch you had installed ahead of time. It runs on gasoline, which you have to have stored or go get. It sits outside in the rain. It powers some things, not everything, depending on what you wired it for.
None of that is a dealbreaker if you are prepared, disciplined, and the outage happens when you are home.
The whole-home standby
It is connected directly to your natural gas or propane supply, so it never runs out of fuel. It starts itself within seconds of detecting a power outage, whether you are home or not. It runs your entire house on the same circuits you use every day. When the grid comes back, it shuts itself off and reconnects automatically.
The trade is cost. A whole-home standby is a significant investment. A portable is not.

The setup that actually gets people
Most homeowners who own a portable generator and experience a serious multi-day outage call me the following spring. Not because the portable failed exactly, but because the manual process of setting it up in the dark during a storm with extension cords running everywhere was miserable, and they realized they never want to do it again.
That is a real data point.
