When we donate, a lot of it is for good-will. If you decide to donate, just donate to any of them. So what this particular piece of money may not go to China, it is used to save other needed people in the world. Similarly, money donated to other causes may be used this time to help Chinese. If you are not comfortable with this, the best way is to go to china and find a specific child to help. Even then, you run the risk of that Child's relatives may be greedy and not use the money on the child.
Bottomline, all these organizations are the same. They need operation costs and overhead to co-ordinate things. US and Canadian red cross are transparent required by law and will tell you these details. Chinese red cross also has overhead and operation cost. They don't need to tell you by law. But it does not mean all your money go to the people.