Choose two GNU/Linux of BSD flavors and see how they compare in features and supported software/hardware. This may help you select the right operating system for your needs.
Some info from informit.com:
Ubuntu is slightly easier to install and use than Debian, and is updated every six months, so if you want the latest and greatest software, Ubuntu is probably a better choice. Like Debian, Ubuntu uses Synaptic and APT for installing software and package updates. It also installs GNOME as the default desktop environment and offers KDE as an alternative.
LWN.net's take:
What Debian gives you over Ubuntu, from a technical standpoint, is more choice. There are three principle release levels: stable, testing, and unstable. There are more packages, over 20k with a couple of additional repositories (including Ubuntu's Universe and Multiverse gets you pretty close). I'm not entirely sure where the CPU architecture support compares, but I believe Debian's going to buy you those odd PPC and MIPS chips where Ubuntu won't. It's not atypical to start a Debian installation as a minimum of packages (a hundred or so fitting within 150 MB) and simply install additional packages (and their dependencies, through the magic of APT) as you need them. You can do this with Ubuntu ... but you're sort of losing the principle advantage of Ubuntu in doing so.
Differences between the distros on the Ubuntu forums:
Debian stable is really stable and slow-moving. Debian Unstable is really fast-paced, a challenge to use and is pretty much as close to bleeding-edge as you would want to be.
Ubuntu takes a small portion of the Debian unstable packages them and patches them to work well and supports them. The release cycle is a predictable six-month period. The reason Ubuntu can release that often is that they only take into account the small subset of packages that are supported.
No, you cannot use Debian repos. You may compile the packages from source packages, but not the binaries.
"Microsoft, Novell, and now Ubuntu join to boost Apple and Debian":
I have happily used SUSE Linux in the past and currently run Ubuntu. I like Ubuntu, even though my friend Logan says that Ubuntu "is a Swahili word that means 'Too stupid to configure Debian.'"
ProgressiveTech.org discusses installing Ubuntu:
I didn’t spend too long on this step since I’ve kept up to date with developments in the Linux world and had pretty much narrowed my choices down to Debian or Ubuntu (a Debian based system).
I’ve used Debian in the past for servers, and while I like it a lot, I wasn’t interested in all the configuration work I’d have to do to get a basic desktop system up and running properly. I’d been hearing a lot of good things about Ubuntu, so I downloaded the CD image, burned a copy, and started the installation.
DesktopLinux.com's take:
Still can't decide? It's time to turn your attention to an online Linux Distribution Chooser quiz created by Daniel Eikeland, a project leader at Norwegian open-source consultancy Zegenie Studios. It's a handy little test, and I've found it surprisingly good.
MouthShut.com helps you choose a Linux variant:
In my case, I did not want to shell out money to buy an OS like SuSE, RedHat Enterprise etc. I also have a slow dialup connection, I use to check mails, not to download ISOs or binary packages. I also don’t like teasers like SuSE, they’ll have to give out a full-sized OS.
Raible Designs compares Ubuntu to OpenSuse:
When I started installing Ubuntu last night, I figured it'd be a breeze. I have a DVI KVM Switch hooked up to a Logitech cordless keyboard/mouse, and Ubuntu immediately recognized them both. However, at 44%, it failed to install gstreamer0.8-jpeg and the installation bailed out. I was able to login to the desktop and (seemingly) get stuff working, but I'm always a bit leary about a failure in the middle of an OS install. After an hour of futzing with it, I tried again and got the same error. Around 1 a.m., I said "screw this" and threw in the Suse DVD.
The OpenSource blog says that:
I believe that Debian and Ubuntu are an example of mutual symbiosis. In other words, their relationship is advantageous to both entities. (Disclaimer: I do not claim to be an expert on this subject. I am just an observer)
A Debian developer has set up a script to track Debian/Ubuntu package differences.
Firefox on Ubuntu versus Debian:
I’m sure many folks are aware of the tension between Mozilla and Debian over the use of the name “Firefox” for the web browser package. A good exchange of comments between Chris Beard of Mozilla, and Mike Hommey of Debian highlights some of the challenges involved.
Kryogenix's take:
What I’d really like to see, in the fullness of time, is this entirely-Free approach be supported by Canonical and the Ubuntu distro, so there are no restricted modules, I don’t get offered the choice between free and non-free video drivers, that sort of thing. My wireless card won’t work, and I’m happy with that.
Jem Report looks at various Linux distros:
This article is meant to help you understand the basic, fundamental differences between GNU/Linux distributions. If you want an in-depth comparison of several distros, your best bet is to find individual reviews of the ones you're interested in and decide for yourself -- don't let others decide for you. Go to Distrowatch, then find the sections for the distros you want to research. Distrowatch provides links to all of the online reviews of each version of every distro that it tracks -- it's an excellent resource for getting a variety of perspectives on many different GNU/Linux distributions.
Debian and Ubuntu: The keyword is freedom:
So, it is very likely that some of those Debian based distributions, in this case Ubuntu, just couldn't do both things at the same time; keep full compatibility and pursue their unique goals. Now I will echo what many said in comments. Ubuntu is a GNU/Linux distribution technically aimed at people who want their OS stable, to "just work" out of the box and at that include the very latest of available software.
Newforcge is concerned with the business side of Debian/Ubuntu:
Politics aside, Ubuntu has diverged enough from Debian that you can no longer assume a Debian package will install and run in Ubuntu or vice versa. And there are other factors that separate Ubuntu from its Debian parent
Another DesktopLinux.com take:
One of my gripes about Kubuntu is when you want to get your hands on the command-line controls. Maybe everyone doesn't want a Linux distribution that has a default terminal window at the top interface, but I do.
