Jeremy Davis's picture

If you want to have separate users but it doesn't matter if the different users can browse and download (read only) through the file heirarchy then you can just use SFTP OOTB (after settig up your users).

If you want to lock the users to their vhost directory then vsftpd or ProFTP are a better bet. I have only ever used vsftpd and have found it very easy to configure manually but there is no Webmin module. As you note there is a ProFTP Webmin module. Instead of installing the 'Webmin way' try using apt-get. IIRC something like 

apt-get update && apt-get install webmin-proftp

should work...