ASP.NET ( and the complimentary MSSQL ) is ALL IIS has to offer, its not enough to say that windows has anything on linux because of one service is can do that linux can't do properly ( yet ), not enough by far ... what about the fact that windows is a targeted platform for attack, what about the fact there are very few good quality opensource or otherwise ASP.NET projects that people might actually want to use, what about the fact that unix is a better operating system ... Windows is highly suitable for very few sites, and Unix is highly suitable for the vast majoritymost clients have no idea what plesk, cpanel, dotnetpanel, helm, blah blah is. All they want is their website up 100% of the time without a hitch. Currently we are using Hsphere and the argument of "I NEEEEEEED cpanel" is squashed upon first login. However if you plan to only sell to freewebspace people then grab the first overselling reseller account you can find and it better have cpanel and you better charge under $3/mo and accept egold and moneybookers.
If you had a choice to be with a host that had 99.9% uptime and had a panel you were not requesting, but does the same thing, or would you rather be with a host that has 98% uptime but has cpanel?
Windows also has ASP.net, exchange, MSSQL database support. Linux does not. Linux can have BASIC asp.net support but it is not pretty.
helpdesk is not about cost it just happens to be included in the package I am getting. free helpdesks do not offer near the functionality that I or most anyone would need. smarterticket and kayako do.
also your argument about whmcs being $10/mo is fine. that brings your total down to $35/mo...still $5 more than windows
point is that cost has nothing to do with windows setups. It has to do with people thinking centos and cpanel is the only way to do hosting because that is what eveyone here says to do. I've used in a production environment Plesk (windows), Cpanel, HSphere, and soon to be dotnetpanel. Plesk and dotne:beer:t seem to be the best of the best and don't randomly break.