More than half the things I own are built in China that's no big deal. they are now the world' second largest economy, just reported to have past Japan today.
As with all things new you probably don't want to buy from the first months production if you can help it, but there is no reasons to suppose Hyundai can't impose their QC in the same way as they did in the Czech plant. They can build the same, train the same, use the sam processes etc.
On opening the Czech plant there seem to have been a few issues with paint quality to start with, and a couple of possibly suspect parts (shock absorber covers and glopugs come to mind) but apart from that (and the obcious cosmetic differences) an i30 is an i30.
Overall I think Hyundai are very good at quality control. I'm sure this will be overseen by expereince technicians from the other factories, as it is in the Czech factory.