<div style='font: 9pt ; text-align: left; '>Face it, both Apache and IIS get hacked with the same frequency and when it comes to OS stability, Win 2000 is starting to get there, the amount of security patches released is starting to slow down by a great deal.
When it comes to cost/scability at enterprise level, the MS combo is quite hard to beat in terms of both cost and performance. Apache/others don't do SMP as well as the current MS combo. Apache is good for HTTP load balancing though, but that just means the requirement for more hardware to achieve the same result as a MS bases SMP cluster when it comes to HTTP related applications.
When it comes to other non internet related applications like terminal logins, again MS is better due to it's SMP scaling performance.
This is why when the DOS attack came, Seoul was practically shut down because a lot of their banks etc runned on MS stuff, and MS did a terrible job advertising the patch to the DOS attack worm.
Apache/*nix/*SQL solutions are good for low to medium-end enterprise applications requirements, and high internet based enterprise applications but it's not as cost efficient when it involves non-internet based applications.
For a more detail look,
http://www.tpc.org/ has more bench mark results at the enteprice level if you are curius.</div>