Nearing 8-10 years of life, what matters is how the PO took care of the vehicle. If the generator has low run hours on it, you probably will need to factor in a new carb. The Ford probably needs some TLC with a Lisle tool to have its spark plugs and coils replaced. Even though they should be pulled at 100K miles, it is always good to get the initial servicing out of the way.
I will say the Chevy has a smaller doghouse, but both platforms are decent. On an even par, I'd choose the Ford, but that is due to being more versed with the brand than Chevy.