From first hand experience, I'll have to agree with Shelton. I won't mention brands, as it may just be my bad luck.
The Chinese engine that came with my small highbanker lasted one summer. Took it to a small engine repair shop, they said it wasn't worth repairing, would cost more than you could buy another one. So I replaced it with a small Honda motor and trash pump. Have used it for three seasons now. Problem solved.
Same thing with a small generator I got for the camper. Stopped running after about 20 - 30 hours of use. Cost more to repair than I paid for it. Replaced it with a Yamaha generator. Haven't used it much yet, so we shall see over time.
I guess we are in a disposable society these days. I personally have a problem with this concept, and perfer to purchase products that provide better and longer service.
By the way, my ATV is a Can-Am that I bought in 2004. It has had a couple minor problems, but repairable at a reasonable cost.
Just my .02 cents worth.