Short bio: Computer Scientist, FOSS supporter (read more)
Tux Machines (TM)-specific
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.
To put them through their paces, I installed each distribution natively on a Dell Inspiron 530S powered by a 2.2GHz Intel Pentium E2200 dual-core processor with an 800MHz front-side bus. The test machine had 4GB of RAM, a 500GB SATA drive and an integrated Intel 3100 GMA chipset.
I also ran the trio on an identical system with MEPIS Linux as the host operating system, in Sun's VirtualBox 3.0.12 virtual machine. Finally, I took turning running Fedora and openSUSE on my Lenovo ThinkPad R61 laptop and ran Ubuntu on my Dell Mini 9 netbook.