The major focus of this new version is to protect the user login names of privileged users from discovery. Which, it turns out, is a lot of work to do correctly.
It includes optional restrictions on password reset attempts and new user registrations. The plugin also helps you see and modify the various names WordPress keep for each user. By default WordPress uses the user login name to construct author archive URLs, nickname, displayname and so on.
It also allows you to change the URL name of users. I actually find it rather strange that there is no way to change it in stock WordPress.
Remaining on the todo list: Translations, the readme.txt, some documentation, and some further testing.