My comment on scalability and Windows is mostly based upon cost as well as most distributed software solutions that are designed to scale are primarily done not on Windows Server but on Linux of some flavor. I am also biased here as I started my career in Unix, although I spent ~8 years doing primarily Microsoft development, and am dedicated to non-microsoft environments now. In some cases when clients have demanded we deploy on Windows some of the software vendors would tell us to significantly increase the number of nodes when running on Microsoft as they found their failure rates were higher, not to mention less resource efficient. Hence cost goes up more and maintenance increases as well. And no, I wouldn't necessarily say Windows is as capable as Linux, but that may just be some bias sneaking in.
