It's the quality control and the fact that the buyer is a continent or ocean away. If a western company has hired a Chinese manufacture, they can get a good product if they stay on top of plant inspections. If not, the Chinese manufacture will start cutting corners. If you're a western buyer, buy from a western company even if a majority of parts were made in China. If you manage to import a whole car from Alibaba and something goes wrong, you're SOL.