We use ProjectSend
Tech-Party File Sharing
There's always a file someone needs, or something we always use and can't find, so we made our own file sharing section.
ProjectSend seems to be a great solution. Again, we chose ProjectSend because it is part of the free suite from Godaddy and had no special setup or conflicts with other apps.
Right now it looks like we have to set up users individually, if you would like access or have an inkling to administrate a file section, contact us.
ProjectSend Developer Blog
(Why admin guides when I'm not an admin? Become an admin, contact us)