Why? Simply put, it keeps things easy to manage. I am able to use a LTS release on any of my daily use boxes while still being free to take the latest Ubuntu releases for a test drive should I wish to from a LiveCD.
So despite Ubuntu being deemed as "too bleeding edge" by some, Ubuntu has proven to be a practical choice for myself personally.
There is also another reason I rely so heavily on Ubuntu. It's where the bulk of the community support is. Add this to the fact that my PCs will run perfectly with the peripherals of my choosing and that having to configure anything out of the ordinary is highly unlikely and Ubuntu becomes the path of least resistance when opting for a Linux lifestyle.
Now consider for a moment: where would users such as myself be if Ubuntu ceased to exist?
Yes, I realize a number of you are quite happy with Debian, OpenSuSE or in some cases, Slackware and Gentoo. But for those of us who are used to what Ubuntu provides, I imagine itd be quite a shocking switch.
Thinking about this today, I forced myself to ponder what I would end up migrating to should Ubuntu suddenly cease to be available. The results of said pondering were not as predictable as I had initially expected.
Taking stock of available Linux alternatives
Despite the belief by some Linux enthusiasts that Debian remains a potential contender as an Ubuntu alternative, there are other distros available that have taken the same Debian core and have done wonderful things with it. Xandros
Distros such as Simply Mepis, for instance. Another option might be Linux Mint. Even though Mint currently uses an Ubuntu base for each release, something tells me that, in a sudden absence of Ubuntu from which to draw from, Mint would find itself moving over to a Debian core in order to continue with future releases.
Xandros is basically Debian, with a pretty looking wrapper. PCLinuxOS and Mandriva are both great RPM-based distros that provide solid alternatives for those who are just not satisfied with what a Debian-based distribution can provide.
In each individual case, most people who are already used to using desktop Linux would find the switch to be a reasonable experience overall.
Which distro is best for the more experienced Linux user?
Speaking for myself, selecting an Ubuntu alternative is a close tie between Linux Mint and PCLinuxOS.
This is not to say that Simply Mepis or Mandriva should be ignored. Rather, I have found that Mint and PCLinuxOS have the most accessible communities when compatibility or installation issues arise. That, and I can easily reach the developers for each distribution without having to field my concerns through a ton of middlemen. I realize this is not a priority for everyone, but it definitely matters a great deal to me.
Another reason I might be inclined to select PCLinuxOS or Linux Mint is the fact that each distro provides its users with community-based solutions to any distro shortcomings. For instance, let's say that theres an issue with getting proprietary drivers installed. Linux Mint was the first distro to provide a third party installer tool called "Envy" included by default with the initial installation.