On my desktop (Precise) I have run System Settings > Details > Install Updates from the Unity desktop. On my cloud server, also on Precise, I can use a VNC session to do the same but instead I have run apt-get update and apt-get upgrade.
Was my desktop activity equivalent to my server activity or is one of these measures less complete?
Was my desktop activity equivalent to my server activity
Most of the time, yes, the desktop update is equal to apt-get update && apt-get upgrade.
However, apt-get upgrade will not install packages like kernel upgrades that are optional but highly recommended, while Update Manager will. You have to use apt-get dist-upgrade for that, in which case you would have a true equivalent.
If you use apt-get upgrade and kernel upgrades, etc. are available, you will see a message like The following packages have been held back:; that's your cue to run apt-get dist-upgrade if you wish to upgrade those packages.
Note that a number of types of cloud servers do not use their own kernel, but their physical "host" machine's kernel (OpenVZ, vserver, LXC, Xen paravirtualized); other types behave like physical machines themselves (Xen HVM, KVM).
