Administration is accomplished through the use of a text file known as the httpd.conf. You couldn't ask for much more out of a web server, and when you look at the price you are easily able to look past the minor disadvantages. If you take the time to learn and understand Apache, you will have the power to create an extremely powerful and efficient web server. IIS is very effective in certain situations, especially when dealing with dynamic content, and database access, but Apache wins hands down. Their product is superb, the price is incredible, and its available on almost any platform.
Documentation is readily available, as well as many other means of supporting their user base.
Product updates come quickly, and modules are created constanly, allowing an administrator the ability to expand the capabilites of Apache on a whim.