If you want to see what is (almost free) but not CVS, here are a couple of options.

The main perl development effort uses something called Perforce. Another almost free option is Bitkeeper. Neither is truly open source. But take a look at them anyways.

Both run under OpenBSD.

There are many, many version control schemes in development out there. One which I would recommend keeping your eyes on is Subversion. It won't be ready for a bit, but there are serious problems with CVS that simply cannot be fixed.

A description of some of what is wrong with CVS can be found here. It is clear that some of the key people in that discussion had not a clue who Simon Cozens is. I would hope that none of them are Perl folks. :-) Anyways that discussion talks a bit about what CVS lacks, and names a few other resources that you might want to look at.