I’ve tried quite a few distros (openSUSE, Ubuntu, Solus, Arch, so on) and none seem to offer this feature. It’s a shame, as it’s quite useful to have since updating a live system can sometimes cause some trouble. Even just the updating from Discover can be broken on some systems (I know openSUSE at the very least acts a bit funny when it comes to PackageKit, I think Arch as well).

Can definitely recommend Fedora too. Software updates are at a good pace, and the system has a lot of polish all around. For example, all you need to do for updates is to press “update” in Discover and it’ll do everything for you, applying on reboot for stability. Most things “just work”.