Centos provides a free enterprise class computing Linux platform to anyone who wishes to use it.
The Free Enterprise Linux from Centos is built from publicly available open source SRPMS provided by a prominent North American Enterprise Linux vendor. CentOS conforms fully with the upstream vendors redistribution policies and aims to be 100% binary compatible.
Usually, an updated version of the Centos Enterprise Linux is available within 72 hours of Red Hat releasing a fix in their enterprise version.
So effectively, the Centos Linux is as good as a free Red Hat Enterprise Linux .