How Microsoft uses Team Foundation Server and a review of Team Foundation Server 2010.
If you need to produce custom code should you use TS over VSS? VSS is still good for teams of at most 5-10 team members. If you go over that you probably need to look at some other system, but Team Server comes with high user cost and frankly it is not the easiest software to learn and deploy, and it comes with some frustrating problem like no ability to link component to their use cases (without cheating).
I guess this question I can answer with this anser: if you need to ask you should not consider Team Server.
Taking a step back the great code version control community has been mostly abuze about going Open Source, which is probably what you should look in to. I have used CVS on a very large project back when I still cut code and it work very well, and the price is right.