On the other hand, if you really like Red Hat, but can't afford it, you can buy into CentOS. In essence, it is RHEL, but without the actual Red Hats or any reference to Red Hat. It's put together by an independent project group with no affiliation. Because RHEL is a corporate type system, change will come more slowly to their distribution then others.
CentOS is a group is a community of open source contributors and users. Typically, CentOS users are organizations and individuals that do not need strong commercial support in order to achieve successful operation, but still insist on as stable a Unix as they can get. CentOS is a 100% compatible rebuild of the Red Hat Enterprise Linux and in full compliance with Red Hat's redistribution requirements. It is for people who need an enterprise class operating system stability without the cost of certification and support.
How can this be? As required, Red Hat releases all source for the product publicly under the terms of the GNU license. CentOS developers use that source code to create a final product which is very similar to RHEL and freely available for download and use by the public. While there are other distributions also derived from the source of RHEL, they do not have the same notoriety. Additionally, CentOS is recognized as being the most current with Red Hat's changes. At the end of the day, your decision will be based on a variety of different factors: the Linux talent on staff, the budget that your customer has and the corporate culture of the company
This was first published in January 2007