dselect-upgrade vs dist-upgrade

["Benedict Verheyen" <linux4bene@pandora.be>]

Hi,

when cloning a system via the dpkg --get-selection, dpkg --set-selection
method, it's advised to do a apt-get dselect-upgrade instead of
apt-get dist-upgrade. I do not understand why.
Also, if you would use aptitude, what would be the correct way
of doing this?

Thanks,
Benedict