Most if not all Seasonic and FSP PSUs are all built in China now too. However, they still have their headquarters in Taiwan, and they own their factories too I believe. So I trust their quality control much more.
Basically not all Chinese products are built in the same place, and quality is all over the board. Some are bad, some are good. What I buy comes down to QC, design, and testing. But I'd still take a Seasonic or FSP unit (or any rebadges of same) over a lesser quality brand given a choice. I've seen many a PSU let out the magic smoke, and sometimes take other hardware with it. It's worth the extra money.