Hello there,
if you update a lot of servers i would use hpsum for the update. Hpsum scans an then pushes the updates needed no more and that is a good thing.
vcrm/vca runs downloads all packages and then runs them all. That costs more networkload and all installers have to run. When it tuns it will install or skip depending if the package is needed, already up to date or needed.
Kind regards,
Andrew