This thread is starting to have the potential to get out of hand, but I am impressed with the civility of the responses from Jason and Kevin so far...I think THAT points to whether they are

or not more than does their choice to buy one of these imported engines.
Arguments for and against the merits of these engines are easy to make. But I think we need to maintain perspective on what people plan to do with the engines once they are installed. Are they the perfect candidate for a tractor that sees occasional use? Probably. Should we expect them to perform identically to the best engines out there under prolonged, hard use? Probably not.
But, in general, it seems that these "clones" do what they are supposed to do often enough to make "risking it" worthwhile for folks. Are there bad ones? Of course there are. But if you
adjust your expectations to align with the bargain prices these bring you'll likely be a satisfied customer. Part of the cost desparity is quality, but other parts include lack of a realistic warranty and lack of a dealer network for this stuff...all of that contributes to the higher cost of a Kohler, Briggs, Honda, or Tecumseh.
Jingoism aside, I think you can make legitimate complaints about the "demise" of American society as a consequence of products like this. Or any import, for that matter, where a comparable domestic product is available. Profits are exported, which means a continuous outflow of US cash to foreign lands - even when the product is assembled here. That money, like oil money, rarely comes back except to buy more of our assets.
But, then again, we all probably shop at Wal-Mart and always look for the best deal. So, how is buying a less expensive, cloned engine different that passing by the WH dealer on the way to the farm store to pick up a belt?
The collapse of the industrial sector is a consequence of us buying our Hondas, Toyotas, Sonys, and other stuff. It is unavoidable in a global economy (the US no longer has the capability to completely isolate itself and still maintain our standard of living), but some day we will have to pay the piper. We need manufacturing jobs for the "middle" to maintain a decent lifestyle. Not everybody can work t McDonalds or Microsoft.
I respect bamboo's views, but think perhaps wording things a little more diplomatically (e.g. "JAP") might have made his points easier to swallow - for me at least. Clearly his experience with these things has been less than pleasant and I have no reason to doubt his impressions of this merchandise - he is probably a much more skilled mechanic than I will ever be. And I am glad to learn from his experience.
My only real ethical dilemma out purchasing one of these things comes from the fact that China has a history of not respecting patents, copyrights, and other intellectual property. Creating a duplicate of another maker's highly technical product and then flooding the market with them at cut rate prices (based on cheap labor, no development or resarch costs, little engineering, and a subsidized currency) makes MY purchasing one of these things a little difficult. But I don't judge what others are doing in this regard.
But, certainly Honda and Yanmar know these things are for sale here and haven't stopped their import yet so perhaps a royalty is being paid. I don't know.
I wish Jason the best of luck with this thing. I know he will not be the last to see how this works and I am glad he is willing to be a guinea pig for the rest of us.
Thanks for all the opinions already expressed and those yet to come!
Steve