C# is an excellent language to make line of business applications. Visual Studio is the best development IDE on the planet. Those two reasons are primary. Despite the horrible GUI, Windows Server 2012 R2 is an excellent server product fit for the enterprise. ReFS file system is excellent and everything "just works". Since version 7.x, IIS is an excellent Web server as well for small and medium sized businesses. Great backup solutions, good failover and let us not forget, MS SQL is superb in terms of quality and rapid development tools it offers.
When running a business, especially a small business with not many manpowers, you want something that "just works" with good support. Our background is in enterprise so the Windows Server was an easy choice for us because we don't have even one minute extra to "fiddle" with stuff. Things must work, always.
Surely a Linux + Apache would also work but these kinds of setups need too much fiddling and when your applications are written in C#, well, Windows Server is the only choice.
