It depends on you your “style” (which user interface you prefer to work with) and it depends on what you intend to do with it.
If you want to run Apache or nginx and MySQL and PHP, get a Linux server because it is much easier to keep this software up-to-date on Linux. Same if you want Postfix/Exim,etc.
If you want to run Exchange or IIS, get Windows, obviously.
You must compare the different solutions and decide what you want then pick your OS accordingly.
Nobody cares if your server OS is Linux, Windows or some other weird option. What matters is what it does.