The real benefit of propane over gasoline, regardless of the size of the generator, is that it won't gum up a carburetor if it sits without running for a long time.
We run about what you are talking about running. We've needed to twice in 31 years for several days each. I just use a gasoline generator, and keep a spare carburetor. I had to put on the spare carb for Irene to get it to run. I ran the gas out of the generator when I put it back up, but ordered another spare carb.
After you decide on size & portable vs Fixed
Common Fuels in order of preference to me...
Natural gas, no storage issues, unlimited supply
Propane Doesn't age or gum, limited supply
Diesel, storage issues, limited supply
Gasoline, storage issues, limited supply
I was multitasking and missed the obvious, did I.:p
Those with portable gasoline ones, do you run them once a month for an hour or so?
That is what we do with ours, if we are are not using it regularly for welding.
We never had a problem with it not running well, as long as we do that.
Ours sometimes doesn't get started for years. That's why I keep a spare carburetor. We have way too many things with motors to start them every month. I do try to will all the small equipment, because those small carburetors need it, but for the generator, it gets used so infrequently that it really takes less time to just get it running when we need it. I don't think we used it at all between hurricanes Fran and Irene.
I run all the gas out of the carburetor, empty the tank, pull the plug and coat the cylinder with oil, but as long as I have a new carb on the shelf, I know I can get it running. It does get stored in a dry, completely closed building.
Propane, I put a propane generator in at my home and installed one at the farm.
Much less fumes and if there are long periods between use, I think propane is better than gas or diesel.