"Many Red Hat clones have sprung up since the company decided to
stop offering free downloads of its flagship operating system.
Distributions like White Box Linux, Lineox Enterprise Linux, Pie
Box Enterprise Linux, and CentOS Linux are among the many projects
that seek to fill the gap between Fedora and Red Hat Enterprise
Linux. I tested the new CentOS 4, and found it to be a worthy
upgrade that brings all the goodness of RHEL to the open source
community.
"At my university, we moved from SUSE and Fedora to CentOS 3.3
shortly after I reviewed 3.3 for NewsForge last year. We run CentOS
on three servers, which handle proxy, email, and intranet services
for about 500 students..."