As for being a sysadmin I really dislike GUI-apt-Tools - and again case proven. First it told me to use NSU. After checking dist-upgrade output I saw that it complained about not enogh free space. So I symlinked /var/cache/apt/archives, after that the dist-upgrade would have started. Tried the GUI again, still no luck. Moved stuff from the rootfs around, to finally get 60MB or so, still no luck. Now doing a dist-upgrade on the console. Not so user-friendly that GUI thingy