What are some alternatives?
When comparing Serv-U FTP Server and Microsoft IIS, you can also consider the following products
vsftpd - Very secure FTP Daemon, a secure, fast FTP server for UNIX systems, including Linux.
Apache HTTP Server - Apache httpd has been the most popular web server on the Internet since April 1996
FileZilla Server - Download FileZilla Server 0.9.60.2 for Windows
Apache Tomcat - An open source software implementation of the Java Servlet and JavaServer Pages technologies
Titan FTP Server - Windows FTP Server with SFTP and SSL. Includes events automation.
LiteSpeed Web Server - LiteSpeed Web Server (LSWS) is a high-performance Apache drop-in replacement.