mine is a 5500 watt continuos load. Not peak load. You want a portable you can move around. That way I can bring it to the neighbors to help them in emergencies.
There will be other suggestions I'm sure, but mine has a transfer switch on the panel. I do not run the electronics, the sine waves from portables will do them no good. Then do a wattage test, and see what you can run at the same time. I usually just run one major appliance at a time, no electric stove, and a few lights. The generator works fine for that.
Get an electrician for a hook up a quick disconnect cord for your heat if you need to, that way may be less expensive than a transfer switch.
I would go for the transfer switch, it is always a good selling point for when you move.
Like I said, mine was cheap, as long as you can run your essentials, you should be ahead of the game. The big units are for the whole house usually, I do not see a real need for big ones ones nowadays. Just a waste in my opinion. And with cold weather stay away from diesel, when the power goes out ,there is nothing to heat the crankcase. Plain old gasoline is something everyone has around and handy in case you run out.