That I have administered several businesses that have had Microsoft and Redhat. The ones with MS usually pay up front and get updates for free and only pay $250 per incident for serious trouble that I couldnt fix. This happened only two or three times in a 10 year period. Under Redhat you get into the door much easier however if you want RHN subscription you have to pay continously for the life of the server. This really adds up and over the life of a typical server the cost is considerably higher than the up front costs of MS. To each their own. I personally use CentOS and Redhat server OS and redirect the YUM updates to an open source repository. Best of both worlds. Teh only thing I dont like about this is that if ALL software were this easy to redirect the pay portion the software development community would die as no one could afford to live. There would be pay support but little new development as even open source developers have to make a living.