It would be a huge expense for us to convert anything to "Free WinServer". We would have to redevelop all of our infrastructure for deploying software, porting

It would be a huge expense for us to convert anything to "Free WinServer". We would have to redevelop all of our infrastructure for deploying software, porting and testing the software, configuring, monitoring, and deploying machines... We're probably talking six figures of time and on top of that the opportunity cost of not working on something else. We already have tools and experience for using Linux for everything that doesn't absolutely require Windows. We really only run Windows for: MS-SQL, our dev workstations, and the backup server for the dev workstations. One real pain point for running Windows is the regular BSA or similar audits. We try very hard to make sure that we are properly licensed, but when the auditor comes knocking we have to spend around a week going through and verifying everything, making sure that no licenses have expired, etc... Even buying servers is made harder with Microsoft... "Ok, the license price specifies X per core and Y for memory, so to hit the licensing and system sweet spot we need this many cores but no more and this much memory." With Linux we can just pick the system sweet spot for our use, and then at the end of the year we send donations to open source projects we use. That can sometimes be painful, (had problems with paypal for some of the most recent donations), but the licensing terms are much more obvious and less specialized.