Thanks. This is good to know!

Is the merge seamless/easy to use? What would happen, in the case of a procedure library, if two developers ended up working on the same procedure? Is VSS 'procedure aware'?

If two developers DO check the same file (which you can only do if it is a PRG-based library, not VCX), VSS gives you the ability to merge the changes of the two files together so that neither developer losses work.