When I thought about these, I talked to the rental shop at Home Depot. The guy there said "If you want to keep it, and you are the kind who will do some basic maintenance, buy a Honda." So I did - an EM2500. It would run anything I needed at the track and also some lights, a space heater and the refrigerator at home (After a hurricane or other power outage.)
One important factor - can you lift/handle/load it by yourself? I could do this one if I had to. If not, you will always need help.
One little trick about my Honda - it has a hidden fuel filter which is a "standpipe" inside the tank at the outlet valve. When I did have a problem after several years that it would run but give up or stall with a load, I found this filter clogged. The manual had a hint to "have the tank and fuel system cleaned by your local Authorized Honda...." so I figured there was something they weren't telling me.
Another really good use for any portable generator is engine pre-heating on cold days: Use some sort of load like a hair dryer so the unit is not just idling. Place the unit in front of the grille/air intake and have some pre-made sheet metal or even sturdy cardboard to blow the waste heat and exhaust into the engine bay. Prop up the hood a bit to let it vent out. There is a LOT more heat available that way than just running the unit to power a block heater, etc. Heats coolant, engine, carbs -all.
With regard to fuel, I just buy non-ethanol gas - look at boat marinas or nearby gas stations. If not used, any left-over can always be put in the tow vehicle so it's fresh - and you have emergency gas for any long stretches of road and the gas station is closed... Joel