Re:What about post-install management? (Score 3, Informative)

As far as I know portage doesn't update configuration files for you. It tells you to run etc-update if there are (possible) updates to configuration files.

etc-update allows you to review the changes and apply or ignore them as you see fit.

I believe you can even protect certain files so portage stops bugging you about them, i.e. I'm pretty sure I do not want to revert /etc/fstab to the installation default when I update baselayout (or whatever package fstab comes in), so I could tell portage to just keep its claws away from that file.