China, or PRC, has issued fewer than 2000 green cards to foreigners every since its foundation, and most of them are issued to people who have Chinese ancestry.
Race. Chinese people are pretty...racist to TBH. But if you are White, it is probably going to benefit you. Good luck if you are people of colors. People hate PC here, but you will hate China for zero PC as well. A part that I really don't like about China, is a lot of people seem to judge others like it is their own damn rights, unacceptable.
Religion. Not really a lot people care, not even the government does, if you just practice yourself. But you are openly advocating about that, people will frown upon you, and will keep you distance.