In brushing up on my SCC metadata, I came across this site, which compares many features of the various (mostly open source) systems out there: CVS, Aegis, Arch, BitKeeper, CMSynergy, Co-Op, Darcs, Monotone, OpenCM, Perforce, Subversion, Superversion, syk, Vesta, and Visual Sourcesafe.
I don’t see SourceGear Vault or (obviously) Team System listed.