I knew this would come up, but Whatsapp is still miles ahead of Wechat regarding privacy. And especially regarding invasions of privacy where the Chinese government is involved, which I am pretty sure Whatsapp is safe from.

First, Whatsapp advertises to have end-to-end encryption, which Wechat doesn't have. Second, your private Wechat conversations can be used against you as evidence in court, while any evidence collected with NSA tools cannot, since it is technically illegal.

If you want privacy from the US government, then you probably shouldn't use Whatsapp. In any other situation it is vastly superior.