My current place of employment is currently in a transition, new ownership has taken over, things are finally getting standardized and proper guidelines are being enforced.
But we are still using VSS, there really isn't any reason for using it other then that's what whats initially setup. We don't use Visual Studio, or any tool really that specifically requires it.
What would be the absolute best argument I can bring up to help convince them that going to something like Subversion would be a much better solution, in the long run.
Even if other people say VSS is broken and corrupts source, if the company hasn't had bad experiences then they should be very cautious about changing. Changing source control system is a huge and risky undertaking, even if you're going to something 'better'.
Lower costs is NOT the main driver for a source control system.