Hi - thanks for adding reviewers to pull requests, that's a really useful feature!
However, it would be even more useful if the notification emails that are issued by a pull request included the name of the reviewer near the top, e.g.,
A new pull request has been opened by Joe Bloggs. Reviewers: John Smith, Jane Smith.
Otherwise if you are following the repository you have to open the pull request to find out who the intended reviewer is.