"Pure-FTPd is a free (BSD), secure, production-quality and standard-conformant FTP server based upon Troll-FTPd. It doesn't provide useless bells and whistles, but focuses on efficiency and ease of use. It provides simple answers to common needs, plus unique useful features for personal users as well as hosting providers."

Works quite well together with ISPMan and LDAP.

Benefits that I found:

See also LinuxLDAP, Networking, ISPMan