Better than the out of support date - how about the lack of features and the chance of corrupted databases?
Have you ever used VSS remotely, over a VPN? I've had horrible data corruption problems with VSS in those circumstances, and I was only 15 miles away! I shudder to think of anyone still using it in remote settings.
At the very least, you want a source control system that uses a reliable data store, preferably a database. Switch to SourceGear Vault if you don't want to switch to TFS. Vault is very similar to VSS as a migration path.
On the other hand, there's a lot more to TFS than just source control. Source control is only the beginning of its features. It also handles bug tracking and other work item tracking; permits Continuous Integration and tracking of all builds, including tracking the success of automated unit tests; performs code coverage analysis and static analysis (and keeps track of the results).
It's really an apples to oranges comparison: they are both fruits, and grow on trees. That's about the end of the similarity.
Oh, and they both use the same path syntax, starting with dollar sign.