My (bad) experience with Chinese brake rotors
I bought some no brand disk brake rotors on e-bay for ~$100. They were so wrapped that the entire motorcycle was vibrating each time I braked. I asked for a replacement and the seller accepted. The new pair of rotors had the exact same problem.
I ended up buying used OEM for ~$200 and they work perfectly.
The picture shows the difference in thickness between the OEM (left) and no brand (right). 5.8mm v 4.5mm.
I am not saying they are all bad, but that is my personal experience.