Out of ten people you know, it's a fair bet 10 never heard of FreeTDS™ and nine don't understand the problem it solves. Lots of places have begun to use Microsoft SQL Server™s in all sorts of ways, and if you adhere to the Microsoft line, there's only one way to connect to them: from a Microsoft OS.
What can FreeTDS™ do that can't be done any other way? Glad you asked. FreeTDS™ can
Connect to every version of either vendor's server, using the same binaries.
Provide a CT-Library for Microsoft SQL Server™. This feature alone allows DBD::Sybase™ and sqsh, among others, to connect to Microsoft's product.
Provide a modern DB-Library for Microsoft SQL Server™: Win32/64, and TDS 7+.
Provide a bcp-capable interface and command-line utility on unix-like operating systems for Microsoft SQL Server™.
Run on many more operating systems than either vendor's libraries do.
Get fixed, instead of telling you to get stuffed.
Amuse and inform. Also frustrate and infuriate, but we don't put that under “Advocacy”.
If more people knew, fewer would be stuck.