We do general client websites with WP and ecom sites for clients with Shopify (as a partner.) Since both leverage their codebase with React, and since we know React, it is in our interest for things to stay as they are. However, I have to agree with most of the others here that given FB's license, React is simply not a good choice for the WP community.

Of course no final decision has been made and so it would not surprise me if WP threw their support behind vue.js as it is fairly similar and has a bit less of a learning curve. (Note: I've not seen vue's license.)

I don't understand why Shopify uses React... you just know that FB is itching to get into its market and when/if they do Shopify may find itself all alone in a place they don't want to be.