The most popular distros that can update automatically with the manager are Mandriva, Fedora, Ubuntu, Debian, Red Hat, OpenSuse, Gentoo, Mint, PCLinuxOS, Arch, Sabayon.
The popular distros that do not do that by default are Slackware, some derivatives and LFS. And they do not for a reason. You can still do it with additional software on those distros.
Anyway, you can still install a new version of slackware and keep your data. For that, you should have a separate /home partition, which is a good idea anyway.
Last edited by Agrouf; 01-21-2010 at 05:42 AM.