With a clean install, there's less chance of an incident, and if you put /home on a separate partition, you don't have to back up your data (although you should, anyway). If you installed extra packages from the repos, you can get them back with:

  dpkg --get-selections > packages.txt

After reinstalling, do

  dpkg --set-selections < packages.txt
  sudo apt-get dselect-upgrade

As for automatic upgrades, that goes against the Linux / free software attitude that the user should be in control of her computer and know what it's doing. I think that's why there's no GUI option for automatic upgrades although unattended-upgrades does exist.