With version 2.7 we've made user and group management much easier to use, especially for organizations with more than a few users. We've added a search box to make finding users and groups easy.
We've also redesigned the editing process. The form is cleaner, and you can now add users to groups right on the same form.
The groups screen got a similar makeover. You can now specify group administrators who can add and remove other users from the group. We've also hidden all of the low-level permissions in a collapsible "Advanced Permissions" box.
All of this is in version 2.7, so be sure to let us know if you want to be a beta tester!