I have a Yamaha YG6600D that I got for nothing off of Craigslist because the carburetor was trashed from bad gas. My BIL had a conversion kit to convert it to propane that was off his old one in their motorhome that he gave me. It starts on the second or third pull every time, even after sitting for several months. I'm a firm believer of propane now.
I also have a Generac 10,000EXL that I got cheap off of CL for the same reason as the Yamaha. I got it running good and used it to power my big welder away from the house, but after a couple of years the carb went bad again because of the gas. Walmart has ethanol free gas here now so I'm definitely getting it going again. I was too cheap to buy the conversion kit for it to be a tri-fuel but that is going to have to be done since I got permission to do it now. Seems like it was just under $300 for one that was big enough for it. I'll have to figure out where I got that info. I have an idea of how to run what's needed in the house off of it using my 50 amp welder plug in the garage, but it would cause nightmares for a code compliance employee.
I got both of them thinking we would need them after a hurricane and never planned on it being a winter storm.