Why Apache Tomcat™ instead of IIS?
Because we can control the installation and configuration of an Apache™ web server during install, we use it as the default web server even though Microsoft IIS is usually available on a Windows 2000/XP/2003 platform. Apache also provides a cleaner servlet container through Tomcat. However, we also provide an IIS Plug-in, and you can configure IIS as the web server if you have a requirement to use Microsoft technologies.