Well, Centos is a free version of RHEL, 7 yrs worth of updates for each major version
http://www.redhat.com/security/updates/errata/.
highly stable.
Also, because RHEL is widely used in major orgs eg NYSE, any serious issues tend to be found and fixed pronto. RH actually employ a lot of the developers.
It's not perfect, nothing is, but it's definitely worth thinking about.
I don't know enough about the others to comment.