Hey Jon,
You should have my PM. The .53 that I broke in on the bench to put in my soon-to-be completed 4* is a great runner. This thing has some serious power. I think like Jeffie said, they had some issues up front with carbs of the wrong size going out with engines, but I think they got those taken care of. One thing I like is that even if it is made in China, you have an american company like Sig standing behind it.
Regards,
Curtis
P.S. The price isn't bad either.