Oh, I've worked with PVCS in the past - it wasn't a bad solution circa 1985 or so. But, it is certainly past its 'best if used by' date.
The only non vendor [Not Serena or a related] site I've found that even mentions PVCS is someting called 'cmcrossroads.com' - browsing their message pages related to PVCS indicates that no one is willingly _starting_ a project using it.
We have some structural issues with the existing PVCS archive organization [need to re-organized their internal structure], so there would not appear to be any time savings relative to moving to a non PVCS system [e.g. subversion].
An advantage here is we are not concerned with supporting any older revisions - just the current production server and the next revision.
A disadvantage is corperate reluctance to use free/open software - even when it is clearly a better choice.