I had an Onan 6500 or 7500. It was a built in China motor, a Honda clone I think. Actually I still have it but it's in my brother's building in Illinois and I don't expect to ask for it back. It ran fine. It had the usual Chinese poor quality plastics and rubber but it's still ready to run. It was easy to drain the gas and carb between uses so that helps a lot. It was the one I referred to earlier than ran our well pump and all the essentials.
Back when I got it 20 years ago, it was a Costco deal for $500 ish.