US has one of the highest total tax rate of both corporate and individuals when taking into account federal tax and state taxes.

i don't know anyone with a startup in Asia, but I can't see starting a company in China being easy.

I'd say Korea most likely has a good infrastructure of a growing tech startup ecosystem. they also have a relatively low corporate tax rate as well as individual rates.

two startups from S. Korea were part of the fbFund I believe.