Josh, keep the big picture in mind with those cheaper generators. 1) they may be noisier, 2) they may not meet CARB requirements, 3) and most important) what is their run time? Are you going to be getting up every 4 hours to go refill the tank?
Plus, like much of the tools/equipment I'm seeing from the cheapo places, yes they are good for the few uses I'm going to be using these tools for. But something as critical as a backup plan for my aquarium, I think I would go with a generator that I can trust more. I'm not saying those cheap ones are bad - just not tested for reliability.
Sure electricity doesn't go down often enough for more than a couple of uses of the generator - but I would want mine to work each time and everytime.
If you've got the space and willingness to store the generator and fuel on standby, I think that's the way to go.
But I've already got fuel and a motor in my car in my driveway/garage. So why not use that intermittantly to maintain the car battery and add an easy to store inverter? YMMV
