WIndows is good for games but not for a server. The company i work for has too a Windows server, i got it easy, to step in, to much security holes, no matter if it is a client or server version.
Example: Maybe you know the 23 year old security hole, from win 95 up to win 8, thats still in windows? So win update on or off, no matter i think. And many more things like that. Better make important things on a OS, thats stable and secure. And why pay for something, that has shit support and is unsecure?