Redemption in a Blog has an interesting link to a Version Control System Comparison.
Serendipity is currently considering moving away from CVS and SourceForge. Honestly I find CVS lacking in many areas and the Sourceforge CVS is painfully slow and 24 hours behind for anonymous users, which is really not acceptable. That said, Sourceforge does provide a good base for projects, their search function is widely used and real alternatives to Sourceforge are hard to come by.