Usually i would go with Auth0, cause of their developer first approach and their better documentation. But the enterprise context it is important that you can rely on the Service that you use.
Since the acquisition, I hesitate to make that decision. What do you guess will happen in the next 1-2 years?
1. Will Okta do as they say, and keep Auth0 around as an alternative Service to their own product?
2. Will they abandon Auth0?
3. Or will they try to fuse their products?