What are some alternatives?
When comparing BulletProof FTP Server and Microsoft IIS, you can also consider the following products
FileZilla Server - Download FileZilla Server 0.9.60.2 for Windows
Apache HTTP Server - Apache httpd has been the most popular web server on the Internet since April 1996
ProFTPD - The Official ProFTPD web site. ProFTPD is a high-performance, extremely configurable, and most of all a secure FTP server, featuring Apache-like configuration and blazing performance.
Apache Tomcat - An open source software implementation of the Java Servlet and JavaServer Pages technologies
vsftpd - Very secure FTP Daemon, a secure, fast FTP server for UNIX systems, including Linux.
LiteSpeed Web Server - LiteSpeed Web Server (LSWS) is a high-performance Apache drop-in replacement.