CentOS 6, the current version, is supported by the year 2020, this means patches will be available until then, even though I don’t anticipate running CentOS 6 in the year 2020 (I’m sure I’d have moved on to CentOS 7, 8, or whatever version is out by then). But this allows a system’s core operating system to run and be supported for well more than two years. I anticipate about five years of having an OS running on any one of the desktops I support. The other reason is that there are a handful of third party repositories for CentOS that have updated packages of software, of which I will get into in a little bit.
So for example, if I had installed a CentOS system in 2010 when it was first released, today I can upgrade the Firefox browser to the newest version. If I had chosen to install Fedora in 2010, I would be stuck with an older version of Firefox unless I could find a version of it released or install it manually. Upgrading the RPM packages with these GNU/Linux distributions is definitely my preferred way of keeping software up to date, because it is very easy to manage and requires much less labour keeping up to date than manually installing programs. In fact, in my opinion it beats Windows software management by leaps and bounds by design.
CentOS also has other advantages as well. It is not cutting edge, and that can be a good thing. It still uses the 2.6.x kernel, and its core packages are older which means that bugs have been worked out and the software should be relatively bug-free overall. In addition, regular releases of CentOS do offer seamless upgrades in case you do want to do a complete refresh of a system. For example, the recently released CentOS 6.5 offers LibreOffice 4 which is fairly modern. All which can run on the CentOS core operating system as the software is kept up to date in a lot of cases.
Current packages that are not available with the core CentOS distribution can be obtained easily by installing a third party distribution. These distributions are widely used and I’ve found the list below is very suitable for getting a very good platform with new software versions.