Cigna and Allianz both have a licensed product in China. I would always encourage my clients to get a locally licensed policies. This way you will have a larger local Direct billing network, local support for claims, local knowledge base for facilities, etc.
Could be worth having a look at NOW Health or AXA ICBC, both good comprehensive policies, never had a problem on their customer service side and their premiums are a lot more competitive. If however, you’re set on either Allianz or Cigna, I’d go with Cigna, its pricey but you get what you pay for. (Local subsidiary is Cigna&CMC)