I have to be honest, I see no reason to even consider paying for a VCS nowadays with excellent options like git and hg available. IMO, commercial VCSes owe their existence to the fact that CVS is garbage for large projects. Now that there are competitive free options available, the only reason I can see to continue paying for a commercial VCS is if you’ve been using it for years and the costs of switching will be enormous.
Edit: Good Lord, though, SourceSafe? Even Microsoft doesn’t use SourceSafe.
Assembla offers free closed source hosting. They allow SVN and git repositories. It’s what I and a friend are using for our project, and we haven’t had anything to complain about so far.
Subversion is my personal favourite. I’ve used it on many cross-platform projects without any problems.
I recently started working at a giant technology company that uses ClearCase as well as a few other Rational products. Those must be some of the shittest software I’ve ever seen. I don’t even want to know how much money has been poured into them and how many otherwise productive hours have been wasted.