Kind of depends what you are coming here for........
If its just for the money then consider Hainan as they pay considerably more especially for the 'live in China' contracts.
If you want to try and have a normal-ish life back home while working for a Chinese carrier then try CSA IF 1 of their 'out bases' are easily commutable for you to get home. 4K/month lower pay though at CSA compared to Hainan so as I mentioned before, kind of depends what you are looking for.
There is also the small issue of passing both selection processes first 😩😩
All the best with whatever you choose.
Cheers,