I've decided that VCs are a great editing tool but not an archival choice. I want everything possible to be read by future software and to survive catalog problems...and so, I have taken to converting VCs that I want to keep as DNGs or Exporting as Originals which keeps the raw file and the xmp. VCs remind me of the problem I see from clients coming to Lr from Aperture...edits and choices (which cost the users time and money) are just missing. I think Lr and Ps are here for the long run but there could certainly be better choices in the future. I've never lost image data since starting with digital images back in the '90s but I have always archived in non-proprietary formats. My 2 cents.