I don't see why the editor doesn't multi-boot a stable and a development version of these
distros - most hard disks are enormous relative to distro sizes these days, and it's easy
enough to set this up along with a separate /home partition. If the development distro
breaks, simply reboot into the stable version and fix the problems from there, with chroot if
needed. This is particularly useful for laptops and where you want good performance when
recovering the development distro.
I really like Ubuntu but I do find its upgrades are not quite as problem-free as advertised,
particularly the dist-upgrades (e.g. update-manager breaks when used with apt-cacher).
Cloning the stable distro before doing an upgrade to a new stable version, or a development
version, is therefore not a bad idea.