FTP server and functionality issue

We are looking into a file transfer method for our organization that is the
most widely compatible. We want to have a secure connection between the client
and server when transfering files. We've decided to go with FTP servers that
support both FTP, FTPS and SFTP. There's this FTP server named "Titan FTP
Server" www.titanftp.com which supports all those interfaces. We like to know
if any of you have had any experience with this software or FTP servers for
windows in general. What would you recommend as a means of file transfer?