For most purposes, csup is a drop-in replacement for cvsup. This program comes with the base system since FreeBSD 6.2, so it does not require bloated dependencies to run.
A benefit of csup is that it is used the same way cvsup is used: it uses the same configuration supfiles, and is generally used the same way on the command line. Csup was adequate for updating ports and the source tree, but it lacks other cvsup mirroring functions. Portsnap is best used to update the ports tree. For purposes of last second bleeding edge, non-revised, updates, portsnap generally updates less often than cvs, since cvs repositories are generally updated on a whim.
Please see the csup manpage for details, and /usr/share/examples/cvs/ for *.supfile examples.
- Network Administration with FreeBSD 7 (2008)