ComputerWorld takes a look at the important distinctions between the Fedora, openSUSE and Ubuntu Linux desktop distros, you can read it over here.
Computerworld - At first glance, there's little to differentiate between the latest releases of the top Linux distributions: Red Hat's Fedora 12, Novell's openSUSE 11.2 and Canonical's Ubuntu 9.10. They each use the latest releases of open-source applications and are based on recent Linux kernels. Each of the distros also includes open-source applications such as OpenOffice and Firefox. However, a closer look reveals real differences -- in fact, each is meant for a different audience.
Underneath the hood, each of the three uses the 2.6.31 Linux kernel, but above that, their differences begin to surface. Fedora and Ubuntu, for example, use GNOME 2.28 (the latest version) for their default desktop, while openSUSE uses KDE 4.3.1.